[
 {
  "term": "1% annual-chance flood",
  "aka": "100-year flood",
  "category": "Climate",
  "definition": "A flood with a 1-in-100 chance of happening in any given year. Climate Ready Boston found today's 1% flood would become a 10% chance by mid-century.",
  "section": "climate",
  "source_url": "https://www.barrfoundation.org/blog/climate-resiliency-efforts-in-boston/"
 },
 {
  "term": "311",
  "aka": "",
  "category": "Data and telecom",
  "definition": "A three-digit number, now also an app and website, for non-emergency city services and information in the US and Canada.",
  "section": "311",
  "source_url": "https://www.govinfo.gov/content/pkg/FR-1997-02-26/html/97-4787.htm"
 },
 {
  "term": "988",
  "aka": "Suicide and Crisis Lifeline",
  "category": "Emergency",
  "definition": "The US three-digit number for mental health crisis calls, texts and chats, live since July 2022.",
  "section": "alarm",
  "source_url": "https://www.gao.gov/products/GAO-26-108114"
 },
 {
  "term": "Accessible pedestrian signal",
  "aka": "APS",
  "category": "Traffic",
  "definition": "A crossing device with a locator tone, vibrating button, tactile arrow and spoken or audible walk cue for blind and low-vision pedestrians.",
  "section": "signals",
  "source_url": "https://www.boston.gov/sites/default/files/document-file-05-2019/aps_pushbutton_may_16_2019.pdf"
 },
 {
  "term": "action level",
  "aka": "",
  "category": "Water",
  "definition": "The concentration of a contaminant, such as lead, that triggers required steps by a water utility. Under the US LCRI it drops from 15 to 10 parts per billion for lead.",
  "section": "water",
  "source_url": "https://www.bhfs.com/insight/leading-the-way-new-epa-rule-gives-10-years-to-replace-lead-drinking-water-service-lines/"
 },
 {
  "term": "Actuated control",
  "aka": "",
  "category": "Traffic",
  "definition": "Signal operation where detectors decide whether a phase is served and how long it lasts.",
  "section": "signals",
  "source_url": "https://nap.nationalacademies.org/read/22097/chapter/14"
 },
 {
  "term": "Adaptive signal control",
  "aka": "",
  "category": "Traffic",
  "definition": "A system that continually retunes splits, cycle lengths and offsets from live detector data instead of fixed plans.",
  "section": "signals",
  "source_url": "https://en.wikipedia.org/wiki/Split_Cycle_Offset_Optimisation_Technique"
 },
 {
  "term": "Advanced metering infrastructure",
  "aka": "AMI, smart meters",
  "category": "History",
  "definition": "Meters that report electricity use back to the utility automatically. Eversource told the Boston City Council it is installing them along with a distribution management system.",
  "section": "stack",
  "source_url": "https://cp.soar.com/articles/7030581/Boston-City/Suffolk-County/Massachusetts/Utilities-tell-Boston-council-undergrounding-is-feasible-but-complex-and-costly-DPU-absence-complicates-oversight-questions"
 },
 {
  "term": "Ampelmännchen",
  "aka": "",
  "category": "Traffic",
  "definition": "The hat-wearing walking-man pedestrian signal from East Germany, kept after reunification and now a Berlin symbol.",
  "section": "signals",
  "source_url": "https://germanhistorydocs.org/en/a-new-germany-1990-2023/east-german-ampelmaennchen"
 },
 {
  "term": "anaerobic digester",
  "aka": "",
  "category": "Sewer",
  "definition": "A sealed tank where bacteria break down sewage sludge without oxygen. Deer Island has 12 egg-shaped ones.",
  "section": "sewer",
  "source_url": "https://en.wikipedia.org/wiki/Deer_Island_Waste_Water_Treatment_Plant"
 },
 {
  "term": "ANI/ALI",
  "aka": "automatic number identification / automatic location identification",
  "category": "Emergency",
  "definition": "The caller's number and the address or location looked up for a legacy 911 call.",
  "section": "alarm",
  "source_url": "https://www.fcc.gov/node/267074"
 },
 {
  "term": "aqueduct",
  "aka": "",
  "category": "Water",
  "definition": "A channel that carries water by gravity from a distant source to a city. Most of Rome's ran underground or at ground level, not on arches.",
  "section": "primer",
  "source_url": "https://en.wikipedia.org/wiki/Roman_aqueduct"
 },
 {
  "term": "Arc lamp",
  "aka": "",
  "category": "Light",
  "definition": "An early electric light that makes a bright, harsh glow from a spark jumping between two carbon rods.",
  "section": "light",
  "source_url": "https://en.wikipedia.org/wiki/Street_light"
 },
 {
  "term": "Astronomical timer",
  "aka": "astronomical clock",
  "category": "Light",
  "definition": "A controller that calculates local sunrise and sunset each day and switches lights accordingly.",
  "section": "light",
  "source_url": "https://en.wikipedia.org/wiki/Street_light"
 },
 {
  "term": "Behind-the-meter solar",
  "aka": "rooftop solar",
  "category": "Power",
  "definition": "Solar panels on a home or business that reduce the demand the grid sees rather than appearing as a power plant.",
  "section": "grid",
  "source_url": "https://iso-ne.com/about/key-stats"
 },
 {
  "term": "booster pump",
  "aka": "",
  "category": "Water",
  "definition": "A pump that raises water pressure so water can reach upper floors or higher ground.",
  "section": "tall",
  "source_url": "https://www.csemag.com/design-basics-for-booster-pumps-in-high-rise-buildings/"
 },
 {
  "term": "Boston Water and Sewer Commission",
  "aka": "BWSC",
  "category": "Government",
  "definition": "The body created by Massachusetts law in 1977, separate from the City of Boston, that runs Boston's local water, sewer and storm drain pipes and sets its own rates.",
  "section": "who",
  "source_url": "https://en.wikipedia.org/wiki/Boston_Water_and_Sewer_Commission"
 },
 {
  "term": "box number",
  "aka": "",
  "category": "Emergency",
  "definition": "The unique number of a fire alarm box, which identifies its location to the alarm office.",
  "section": "alarm",
  "source_url": "https://www.bostonglobe.com/2026/04/03/metro/fire-alarm-boxes/"
 },
 {
  "term": "building code",
  "aka": "",
  "category": "Rules",
  "definition": "Technical rules for how buildings must be built safely, covering structure, fire, plumbing, electrical and energy.",
  "section": "rules",
  "source_url": ""
 },
 {
  "term": "cab signaling",
  "aka": "",
  "category": "Transit",
  "definition": "A system that shows the allowed speed inside the train cab instead of only on trackside lights.",
  "section": "transit",
  "source_url": "https://www.mass.gov/doc/appendix-b-mbta-system-description/download"
 },
 {
  "term": "capital plan",
  "aka": "capital budget",
  "category": "Money",
  "definition": "A multi-year plan for building or repairing long-lived assets like schools, roads and pipes, usually paid for with borrowed money.",
  "section": "money",
  "source_url": "https://www.boston.gov/node/16575796"
 },
 {
  "term": "Carrier hotel",
  "aka": "",
  "category": "History",
  "definition": "A building where many telecom networks place equipment and connect to each other. Boston's internet exchange runs at One Summer Street, a datacenter run by Markley Group.",
  "section": "stack",
  "source_url": "https://en.wikipedia.org/wiki/Boston_Internet_Exchange"
 },
 {
  "term": "central station",
  "aka": "power station",
  "category": "Power",
  "definition": "A plant that generates electricity for many customers over a network of wires, instead of each building making its own.",
  "section": "primer",
  "source_url": "https://ethw.org/Milestones:Pearl_Street_Station"
 },
 {
  "term": "certificate of occupancy",
  "aka": "",
  "category": "Rules",
  "definition": "An official document confirming that a finished building meets the codes and may be used.",
  "section": "rules",
  "source_url": ""
 },
 {
  "term": "cesspit",
  "aka": "",
  "category": "Waste",
  "definition": "A pit beneath or beside a building where human waste collected until someone emptied it.",
  "section": "primer",
  "source_url": "https://en.wikipedia.org/wiki/Gong_farmer"
 },
 {
  "term": "chloramine",
  "aka": "monochloramine",
  "category": "Water",
  "definition": "A long-lasting disinfectant made by combining chlorine and ammonia that keeps water safe as it travels through the pipes.",
  "section": "water",
  "source_url": "https://www.mwra.com/node/1437"
 },
 {
  "term": "climate adaptation",
  "aka": "",
  "category": "Climate",
  "definition": "Changes to infrastructure and planning that reduce harm from climate impacts like flooding and heat.",
  "section": "primer",
  "source_url": "https://www.adaptationclearinghouse.org/resources/climate-ready-boston.html"
 },
 {
  "term": "Climate Ready Boston",
  "aka": "",
  "category": "Climate",
  "definition": "Boston's climate study, released in December 2016, that set out sea level rise and flood risk projections for the city.",
  "section": "climate",
  "source_url": "https://www.barrfoundation.org/blog/climate-resiliency-efforts-in-boston/"
 },
 {
  "term": "Color temperature",
  "aka": "CCT",
  "category": "Light",
  "definition": "A measure in kelvins of how warm (low K, yellow) or cool (high K, blue-white) a white light looks. The AMA recommended 3000K or lower for streets in 2016.",
  "section": "light",
  "source_url": "https://www.npr.org/sections/thetwo-way/2016/06/21/482936520/bright-bluish-white-led-streetlamps-bad-for-our-health-ama-says"
 },
 {
  "term": "combined sewer",
  "aka": "",
  "category": "Sewer",
  "definition": "A single pipe network that carries both household sewage and street stormwater.",
  "section": "sewer",
  "source_url": "https://www.epa.gov/npdes/combined-sewer-overflow-basics"
 },
 {
  "term": "combined sewer overflow",
  "aka": "CSO",
  "category": "Sewer",
  "definition": "The release of untreated sewage and stormwater through a relief outfall when rain overloads a combined sewer.",
  "section": "sewer",
  "source_url": "https://www.epa.gov/npdes/combined-sewer-overflow-basics"
 },
 {
  "term": "Commercial waste zone",
  "aka": "CWZ",
  "category": "Waste",
  "definition": "In New York, one of 20 districts where only three authorized private carters may collect business trash, plus five citywide carters for large containers.",
  "section": "waste",
  "source_url": "https://www.nyc.gov/site/dsny/news/25-001/as-today-first-nyc-commercial-waste-zone-fully-implemented"
 },
 {
  "term": "Composite liner",
  "aka": "",
  "category": "Waste",
  "definition": "The bottom layer of a modern US landfill cell: a plastic geomembrane laid over two feet of compacted clay.",
  "section": "waste",
  "source_url": "https://www.epa.gov/landfills/municipal-solid-waste-landfills"
 },
 {
  "term": "Containerization",
  "aka": "",
  "category": "Waste",
  "definition": "Requiring trash to go into sealed bins instead of bags on the sidewalk, largely to cut off food for rats.",
  "section": "waste",
  "source_url": "https://www.nyc.gov/site/dsny/news/25-039/nyc-rats-fleeing-an-incredible-12-straight-months-"
 },
 {
  "term": "Contamination",
  "aka": "",
  "category": "Waste",
  "definition": "Items that do not belong in a recycling bin, or recyclables too dirty to sell. China's National Sword set a 0.5% limit on it for scrap imports.",
  "section": "waste",
  "source_url": "https://www.buffalo.edu/news/releases/2022/03/029.html"
 },
 {
  "term": "Controller",
  "aka": "Signal controller",
  "category": "Traffic",
  "definition": "The small, ruggedized computer in a roadside cabinet that decides which movements get green and for how long.",
  "section": "signals",
  "source_url": "https://www.marc.org/sites/default/files/2023-03/OGL-traffic-signal-basics.pdf"
 },
 {
  "term": "Controller cabinet",
  "aka": "",
  "category": "Traffic",
  "definition": "The metal box at the corner of an intersection that holds the controller, detector cards, power and safety equipment.",
  "section": "signals",
  "source_url": "https://www.marc.org/sites/default/files/2023-03/OGL-traffic-signal-basics.pdf"
 },
 {
  "term": "corrosion control",
  "aka": "",
  "category": "Water",
  "definition": "Adjusting water chemistry, such as pH and alkalinity, so the water dissolves less lead and copper from old pipes.",
  "section": "water",
  "source_url": "https://www.mwra.com/node/1437"
 },
 {
  "term": "creep",
  "aka": "epoxy creep",
  "category": "Roads",
  "definition": "Slow deformation of a material under constant load. Creep in epoxy adhesive let the Big Dig ceiling anchors pull out in 2006.",
  "section": "roads",
  "source_url": "https://www.npr.org/2007/07/10/11852203/report-epoxy-blamed-in-fatal-big-dig-accident"
 },
 {
  "term": "Critical facility",
  "aka": "",
  "category": "History",
  "definition": "A site a utility restores ahead of ordinary customers after an outage. Eversource lists hospitals, police and fire stations, and water and sewage plants.",
  "section": "stack",
  "source_url": "https://www.eversource.com/business/outages/restoration-process/assessing-damage-and-restoring-power"
 },
 {
  "term": "Cycle length",
  "aka": "",
  "category": "Traffic",
  "definition": "The time a signal takes to go through its complete sequence of phases once.",
  "section": "signals",
  "source_url": "https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter6.htm"
 },
 {
  "term": "debt exclusion",
  "aka": "",
  "category": "Money",
  "definition": "A voter-approved temporary tax increase that covers the loan payments on a specific capital project.",
  "section": "money",
  "source_url": "https://www.mass.gov/doc/chapter-3-proposition-2-12/download"
 },
 {
  "term": "Dig Safe",
  "aka": "811; call before you dig",
  "category": "Roads",
  "definition": "The Massachusetts nonprofit notification center that has utilities mark buried lines before anyone digs; notice is required 72 business hours ahead.",
  "section": "roads",
  "source_url": "https://www.mass.gov/guides/about-dig-safe"
 },
 {
  "term": "digital twin",
  "aka": "",
  "category": "Data and telecom",
  "definition": "A detailed digital model of a city or system used to simulate and plan changes, such as Virtual Singapore.",
  "section": "311",
  "source_url": "https://en.wikipedia.org/wiki/Virtual_Singapore"
 },
 {
  "term": "direct current",
  "aka": "DC",
  "category": "Power",
  "definition": "Electricity that flows in one direction. Early systems like Pearl Street used low-voltage DC.",
  "section": "primer",
  "source_url": "https://ethw.org/Milestones:Pearl_Street_Station"
 },
 {
  "term": "dispatchable location",
  "aka": "",
  "category": "Emergency",
  "definition": "A street address plus details such as floor or apartment that responders can actually go to.",
  "section": "alarm",
  "source_url": "https://www.tlp.law/2025/04/03/fcc-adopts-fnprm-aimed-at-improving-911-location-accuracy/"
 },
 {
  "term": "Distribution feeder",
  "aka": "feeder",
  "category": "Power",
  "definition": "A medium-voltage line that carries power from a substation through a neighborhood.",
  "section": "grid",
  "source_url": "https://www.coserv.com/safety/electric/power-pole-anatomy/"
 },
 {
  "term": "Distribution transformer",
  "aka": "",
  "category": "Power",
  "definition": "The can on a pole, box on a pad or unit in a vault that lowers voltage to what buildings use.",
  "section": "grid",
  "source_url": "https://www.coserv.com/safety/electric/power-pole-anatomy/"
 },
 {
  "term": "District steam",
  "aka": "district energy",
  "category": "Gas and steam",
  "definition": "A system that makes steam at central plants and pipes it under the streets to heat many buildings.",
  "section": "gas-steam",
  "source_url": "https://en.wikipedia.org/wiki/New_York_City_steam_system"
 },
 {
  "term": "eminent domain",
  "aka": "compulsory purchase (UK)",
  "category": "Government",
  "definition": "The government's power to take private property for public use, with payment to the owner.",
  "section": "primer",
  "source_url": "https://www.massmoments.org/moment-details/quabbin-reservoir-filled-to-the-brim.html"
 },
 {
  "term": "enterprise fund",
  "aka": "",
  "category": "Money",
  "definition": "A self-supporting government account, common for water and sewer, where user fees pay the system's costs instead of the property tax.",
  "section": "money",
  "source_url": "https://en.wikipedia.org/wiki/Boston_Water_and_Sewer_Commission"
 },
 {
  "term": "ESInet",
  "aka": "Emergency Services IP Network",
  "category": "Emergency",
  "definition": "The IP network that carries NG911 traffic to call centers.",
  "section": "alarm",
  "source_url": "https://www.fcc.gov/node/267074"
 },
 {
  "term": "eSteam",
  "aka": "",
  "category": "Gas and steam",
  "definition": "Vicinity Energy's name for steam made with electricity instead of by burning fuel.",
  "section": "gas-steam",
  "source_url": "https://www.vicinityenergy.us/locations/boston/"
 },
 {
  "term": "Extended producer responsibility",
  "aka": "EPR",
  "category": "Waste",
  "definition": "A law that makes companies selling packaged products pay for collecting and recycling the packaging, usually through a producer responsibility organization.",
  "section": "waste",
  "source_url": "https://www.lightnowblog.com/2025/12/7-states-have-epr-packaging-laws-5-more-assessing-need"
 },
 {
  "term": "filtration avoidance",
  "aka": "filtration waiver",
  "category": "Water",
  "definition": "Official permission for a utility to skip filtering its water because its protected source stays consistently clean.",
  "section": "water",
  "source_url": "https://www.nrdc.org/experts/eric-goldstein/new-filtration-waiver-poses-challenges-nyc-water-supply"
 },
 {
  "term": "fire alarm telegraph",
  "aka": "",
  "category": "Emergency",
  "definition": "A network of street boxes wired to a central office; pulling a box sends its number so the office knows where the alarm came from. Boston opened the first municipal system in 1852.",
  "section": "alarm",
  "source_url": "https://ethw.org/Milestones:Electric_Fire_Alarm_System,_1852"
 },
 {
  "term": "FirstNet",
  "aka": "",
  "category": "Emergency",
  "definition": "The US nationwide broadband network for public safety, run by AT&T on 700 MHz Band 14 under a 25-year contract.",
  "section": "alarm",
  "source_url": "https://urgentcomm.com/public-safety/firstnet-tops-6-7-million-connections-29-5k-agencies-at-t-reports"
 },
 {
  "term": "flexible pavement",
  "aka": "",
  "category": "Roads",
  "definition": "An asphalt road surface laid on a base of angular crushed rock over the native soil.",
  "section": "roads",
  "source_url": "https://practical.engineering/blog/2020/8/31/how-do-potholes-work"
 },
 {
  "term": "Fused cutout",
  "aka": "cutout",
  "category": "Power",
  "definition": "A fused switch on a pole that disconnects a faulted transformer so one failure does not take down the whole line.",
  "section": "grid",
  "source_url": "https://www.coserv.com/safety/electric/power-pole-anatomy/"
 },
 {
  "term": "Gas regulator",
  "aka": "pressure regulator",
  "category": "History",
  "definition": "A valve that steps gas pressure down and opens or closes to hold the pressure downstream steady, often guided by a sensing line.",
  "section": "stack",
  "source_url": "https://www-s.ntsb.gov/news/press-releases/Pages/NR20190924.aspx"
 },
 {
  "term": "gong farmer",
  "aka": "nightman",
  "category": "Waste",
  "definition": "A worker in Tudor England who emptied privies and cesspits, allowed to work only between 9 pm and 5 am.",
  "section": "primer",
  "source_url": "https://en.wikipedia.org/wiki/Gong_farmer"
 },
 {
  "term": "gray infrastructure",
  "aka": "",
  "category": "Sewer",
  "definition": "Pipes, tanks and tunnels that collect and store stormwater and sewage, as opposed to plant- and soil-based approaches.",
  "section": "sewer",
  "source_url": "https://www.epa.gov/npdes/combined-sewer-overflow-solutions-management-approaches"
 },
 {
  "term": "green infrastructure",
  "aka": "",
  "category": "Sewer",
  "definition": "Plant or soil systems and permeable surfaces, such as rain gardens and green roofs, that manage stormwater where it falls.",
  "section": "sewer",
  "source_url": "https://www.epa.gov/npdes/combined-sewer-overflow-solutions-management-approaches"
 },
 {
  "term": "Green wave",
  "aka": "Progression",
  "category": "Traffic",
  "definition": "A string of signals timed so a vehicle at the planned speed meets green after green.",
  "section": "signals",
  "source_url": "https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter6.htm"
 },
 {
  "term": "GSEP",
  "aka": "Gas System Enhancement Plan",
  "category": "Gas and steam",
  "definition": "The Massachusetts program, created by a 2014 law, that lets gas utilities recover the cost of replacing leak-prone pipe.",
  "section": "gas-steam",
  "source_url": "https://atholdailynews.com/2025/05/02/dpu-confronts-utilities-on-gas-pipe-replacement-60968273/"
 },
 {
  "term": "GTFS",
  "aka": "General Transit Feed Specification",
  "category": "Transit",
  "definition": "A shared file format agencies use to publish routes, stops and schedules so any app can read them. It began with Portland's TriMet and Google in 2005.",
  "section": "transit",
  "source_url": "https://beyondtransparency.org/part-2/pioneering-open-data-standards-the-gtfs-story/"
 },
 {
  "term": "GTFS-Realtime",
  "aka": "GTFS-RT",
  "category": "Transit",
  "definition": "A companion live feed that shares delays, vehicle positions and service alerts.",
  "section": "transit",
  "source_url": "https://en.wikipedia.org/wiki/GTFS"
 },
 {
  "term": "High-pressure sodium",
  "aka": "HPS",
  "category": "Light",
  "definition": "A discharge lamp with an orange-pink light that became the preferred street lamp in the late 20th century.",
  "section": "light",
  "source_url": "https://en.wikipedia.org/wiki/Street_light"
 },
 {
  "term": "ice lens",
  "aka": "",
  "category": "Roads",
  "definition": "A layer of ice that forms between pavement and base in freezing weather; when it thaws it leaves a void under the road.",
  "section": "roads",
  "source_url": "https://practical.engineering/blog/2020/8/31/how-do-potholes-work"
 },
 {
  "term": "independent authority",
  "aka": "public authority",
  "category": "Government",
  "definition": "A public body created by law to run a system like transit, water or an airport, with its own board and budget, outside direct city control.",
  "section": "who",
  "source_url": "https://en.wikipedia.org/wiki/Massachusetts_Water_Resources_Authority"
 },
 {
  "term": "Inductive loop",
  "aka": "Loop detector",
  "category": "Traffic",
  "definition": "A coil of wire laid in sealed saw cuts in the pavement that detects a vehicle through the change in its inductance.",
  "section": "signals",
  "source_url": "https://www.fhwa.dot.gov/publications/research/operations/its/06108/01.cfm"
 },
 {
  "term": "intercepting sewer",
  "aka": "",
  "category": "Waste",
  "definition": "A large sewer that collects the flow of many smaller sewers before it reaches a river and carries it somewhere else.",
  "section": "primer",
  "source_url": "https://ice.org.uk/what-is-civil-engineering/infrastructure-projects/london-sewer-system"
 },
 {
  "term": "Interdependency",
  "aka": "",
  "category": "History",
  "definition": "Our term for the way city systems rely on each other, so that a failure in one, such as power, can spread to others, such as water pumps, signals and trains.",
  "section": "stack",
  "source_url": "https://www.eversource.com/business/outages/restoration-process/assessing-damage-and-restoring-power"
 },
 {
  "term": "internet exchange point",
  "aka": "IXP",
  "category": "Data and telecom",
  "definition": "A shared switch where networks swap traffic directly; Boston's runs at One Summer Street.",
  "section": "311",
  "source_url": "https://en.wikipedia.org/wiki/Boston_Internet_Exchange"
 },
 {
  "term": "investment gap",
  "aka": "",
  "category": "Money",
  "definition": "The difference between what is needed to bring infrastructure to a good state of repair and what is actually being spent. ASCE put the US gap at $3.7 trillion over 10 years in 2025.",
  "section": "money",
  "source_url": "https://www.asce.org/publications-and-news/civil-engineering-source/society-news/article/2025/03/25/asce-report-card-gives-us-infrastructure-highest-ever-c-grade"
 },
 {
  "term": "IPAWS",
  "aka": "Integrated Public Alert and Warning System",
  "category": "Emergency",
  "definition": "FEMA's hub that relays authorized alerts to wireless carriers for broadcast to phones.",
  "section": "alarm",
  "source_url": "https://www.weather.gov/news/062422-wea-10yr"
 },
 {
  "term": "ISO / RTO",
  "aka": "independent system operator; regional transmission organization",
  "category": "Power",
  "definition": "An organization that runs a region's high-voltage grid and wholesale electricity market, separate from the utilities that own local wires.",
  "section": "grid",
  "source_url": "https://iso-ne.com/about/key-stats"
 },
 {
  "term": "jetty",
  "aka": "jettied floor",
  "category": "Rules",
  "definition": "An upper floor that overhangs the floor below. London banned them after the 1666 fire.",
  "section": "primer",
  "source_url": "https://en.wikipedia.org/wiki/Rebuilding_of_London_Act_1666"
 },
 {
  "term": "landfill",
  "aka": "made land",
  "category": "Rules",
  "definition": "Ground created by filling marshes or tidal flats with earth and gravel, as in Boston's Back Bay.",
  "section": "primer",
  "source_url": "https://en.wikipedia.org/wiki/Back_Bay,_Boston"
 },
 {
  "term": "Leachate",
  "aka": "garbage juice",
  "category": "Waste",
  "definition": "The liquid that seeps down through buried garbage; landfills collect and remove it from on top of the liner.",
  "section": "waste",
  "source_url": "https://www.epa.gov/landfills/municipal-solid-waste-landfills"
 },
 {
  "term": "Lead and Copper Rule Improvements",
  "aka": "LCRI",
  "category": "Water",
  "definition": "A 2024 US EPA rule requiring most water systems to replace lead service lines within 10 years, with replacement complete by December 31, 2037.",
  "section": "water",
  "source_url": "https://www.tn.gov/content/dam/tn/environment/water/compliance/wr_dw-lcri-quick-guide-service-line-replacements.pdf"
 },
 {
  "term": "Leading pedestrian interval",
  "aka": "LPI",
  "category": "Traffic",
  "definition": "A 3-7 second walk signal shown before parallel traffic gets its green.",
  "section": "signals",
  "source_url": "https://dot.ca.gov/-/media/dot-media/programs/safety-programs/documents/policy/21-01-lpi-guidance-and-memo-090221-a11y.pdf"
 },
 {
  "term": "Leak-prone pipe",
  "aka": "",
  "category": "Gas and steam",
  "definition": "Old cast-iron or unprotected steel gas pipe that is prone to cracking and leaking. Massachusetts had 4,049 miles left in 2025.",
  "section": "gas-steam",
  "source_url": "https://atholdailynews.com/2025/05/02/dpu-confronts-utilities-on-gas-pipe-replacement-60968273/"
 },
 {
  "term": "levy ceiling",
  "aka": "",
  "category": "Money",
  "definition": "Under Proposition 2½, an absolute cap on the property tax levy of 2.5% of the total assessed value of property in a town.",
  "section": "money",
  "source_url": "https://www.mass.gov/doc/chapter-3-proposition-2-12/download"
 },
 {
  "term": "levy limit",
  "aka": "",
  "category": "Money",
  "definition": "Under Proposition 2½, the most property tax a Massachusetts city may raise in a year. It grows 2.5% a year plus new growth from construction.",
  "section": "money",
  "source_url": "https://www.mass.gov/doc/chapter-3-proposition-2-12/download"
 },
 {
  "term": "Load switch",
  "aka": "",
  "category": "History",
  "definition": "A device in a signal cabinet that turns the controller's 12-volt DC logic into the 120-volt AC power that lights the lamps.",
  "section": "stack",
  "source_url": "https://www.access-board.gov/research/prow/interfacing-aps/appendix-a/"
 },
 {
  "term": "Malfunction management unit",
  "aka": "MMU; conflict monitor",
  "category": "Traffic",
  "definition": "An independent safety device that watches the signal outputs and forces the intersection into flash if it sees conflicting greens or bad voltages.",
  "section": "signals",
  "source_url": "https://www.access-board.gov/research/prow/interfacing-aps/appendix-a/"
 },
 {
  "term": "Manhole event",
  "aka": "",
  "category": "Power",
  "definition": "A fire, smoke or explosion in an underground electrical structure, most often caused by failing cable insulation.",
  "section": "grid",
  "source_url": "https://www.nbcnews.com/business/energy/flying-manhole-covers-n411921"
 },
 {
  "term": "Massachusetts Water Resources Authority",
  "aka": "MWRA",
  "category": "Government",
  "definition": "A state authority created in 1985 that supplies wholesale water and sewage treatment to 61 municipalities in the Boston area.",
  "section": "who",
  "source_url": "https://en.wikipedia.org/wiki/Massachusetts_Water_Resources_Authority"
 },
 {
  "term": "master box",
  "aka": "",
  "category": "Emergency",
  "definition": "A fire alarm box connected to a building such as a school, hospital or library that reports straight to the fire department.",
  "section": "alarm",
  "source_url": "https://www.bostonglobe.com/2026/04/03/metro/fire-alarm-boxes/"
 },
 {
  "term": "Materials recovery facility",
  "aka": "MRF",
  "category": "Waste",
  "definition": "A plant that sorts mixed recyclables into bales of paper, metal and plastic for sale.",
  "section": "waste",
  "source_url": "https://wastedive.com/news/boston-zero-waste-rfi-collection-recycling-disposal-contracts/732052"
 },
 {
  "term": "Mercaptan",
  "aka": "odorant",
  "category": "Gas and steam",
  "definition": "A sulfur compound added to odorless natural gas so leaks smell like rotten eggs.",
  "section": "gas-steam",
  "source_url": "https://news.wisconsinpublicservice.com/?p=264"
 },
 {
  "term": "miasma theory",
  "aka": "bad air",
  "category": "Sewer",
  "definition": "The old belief that diseases like cholera spread through foul-smelling air rather than through contaminated water.",
  "section": "primer",
  "source_url": "https://www.londonmuseum.org.uk/collections/london-stories/john-snow-cholera-broad-street-pump/"
 },
 {
  "term": "multiple-unit control",
  "aka": "",
  "category": "Transit",
  "definition": "Frank Sprague's invention that lets one operator control the motors in every car of a train at once.",
  "section": "transit",
  "source_url": "https://en.wikipedia.org/wiki/Frank_J._Sprague"
 },
 {
  "term": "municipal bond",
  "aka": "muni",
  "category": "Money",
  "definition": "A loan investors make to a state, city or public authority, repaid with interest over a set period, often to pay for capital projects.",
  "section": "money",
  "source_url": "https://www.sifma.org/research/statistics/us-municipal-bonds-statistics"
 },
 {
  "term": "Municipal solid waste",
  "aka": "MSW",
  "category": "Waste",
  "definition": "Everyday trash from homes, schools, offices and shops, as distinct from industrial or hazardous waste.",
  "section": "waste",
  "source_url": "https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/national-overview-facts-and-figures-materials"
 },
 {
  "term": "MUTCD",
  "aka": "Manual on Uniform Traffic Control Devices",
  "category": "Traffic",
  "definition": "The US federal rulebook for traffic signals, signs and markings; the 11th edition took effect in 2024.",
  "section": "signals",
  "source_url": "https://mutcd.fhwa.dot.gov/index.htm"
 },
 {
  "term": "National Bridge Inspection Standards",
  "aka": "NBIS",
  "category": "Roads",
  "definition": "US federal rules that set how often and how public bridges must be inspected, first published in 1971.",
  "section": "roads",
  "source_url": "https://www.fhwa.dot.gov/bridge/nbis.cfm"
 },
 {
  "term": "National Sword",
  "aka": "",
  "category": "Waste",
  "definition": "A Chinese policy launched in 2017 that in 2018 banned many scrap imports, including plastics, and set a 0.5% contamination limit.",
  "section": "waste",
  "source_url": "https://www.buffalo.edu/news/releases/2022/03/029.html"
 },
 {
  "term": "Network protector",
  "aka": "",
  "category": "Power",
  "definition": "A switch in an underground vault that opens when power would flow backward from the network into a dead primary feeder.",
  "section": "grid",
  "source_url": "https://en.wikipedia.org/wiki/Network_protector"
 },
 {
  "term": "NFPA 1710",
  "aka": "",
  "category": "Emergency",
  "definition": "A US consensus standard for career fire departments setting turnout and travel time targets, such as 80 seconds turnout and 240 seconds travel for the first engine.",
  "section": "alarm",
  "source_url": "https://fems.dc.gov/page/fire-response-time"
 },
 {
  "term": "NG911",
  "aka": "Next Generation 911",
  "category": "Emergency",
  "definition": "An internet-protocol 911 system that can carry voice, text, images and location embedded in the call.",
  "section": "alarm",
  "source_url": "https://www.fcc.gov/node/267074"
 },
 {
  "term": "night soil",
  "aka": "",
  "category": "Waste",
  "definition": "Human waste collected from cesspits and privies, usually at night, and carted away, often to fertilize farmland.",
  "section": "primer",
  "source_url": "https://en.wikipedia.org/wiki/Gong_farmer"
 },
 {
  "term": "NTCIP",
  "aka": "National Transportation Communications for ITS Protocol",
  "category": "Traffic",
  "definition": "A family of US standards that lets central computers communicate with signal controllers and other roadside devices from different makers.",
  "section": "signals",
  "source_url": "https://www.ite.org/technical-resources/topics/standards/ntcip-1202-v04-actuated-signal-control-asc/"
 },
 {
  "term": "obligated funds",
  "aka": "",
  "category": "Money",
  "definition": "Federal money legally committed to a specific project, even if it has not yet been paid out.",
  "section": "money",
  "source_url": "https://www.ntu.org/foundation/detail/congress-should-account-for-unspent-infrastructure-funds-before-passing-another-highway-bill"
 },
 {
  "term": "Offset",
  "aka": "",
  "category": "Traffic",
  "definition": "The time relationship between a signal's cycle and a master clock, used to line up neighboring signals into a green wave.",
  "section": "signals",
  "source_url": "https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter6.htm"
 },
 {
  "term": "open data portal",
  "aka": "",
  "category": "Data and telecom",
  "definition": "A government website that publishes datasets for anyone to download and reuse, such as Analyze Boston.",
  "section": "311",
  "source_url": "https://blogs.microsoft.com/newengland/2017/03/30/analyze-boston-new-open-data-hub-helps-citizens-visualize-their-lives/"
 },
 {
  "term": "open-loop payment",
  "aka": "tap-to-ride; contactless",
  "category": "Transit",
  "definition": "Paying a fare by tapping your own bank card or phone instead of an agency-issued card.",
  "section": "transit",
  "source_url": "https://masstransitmag.com/technology/fare-collection/news/55130435/ma-mbta-contactless-payment-goes-live-a-roughly-1-billion-investment"
 },
 {
  "term": "Open311",
  "aka": "",
  "category": "Data and telecom",
  "definition": "An open standard API that lets apps submit and track service requests in city 311 systems.",
  "section": "311",
  "source_url": "https://en.wikipedia.org/wiki/311_(telephone_number)"
 },
 {
  "term": "operating budget",
  "aka": "",
  "category": "Money",
  "definition": "The yearly spending plan for running services, such as salaries, fuel and supplies, paid mostly from taxes, fees and aid.",
  "section": "money",
  "source_url": "https://www.boston.gov/node/16575796"
 },
 {
  "term": "outfall",
  "aka": "",
  "category": "Sewer",
  "definition": "The pipe or tunnel end where treated wastewater, or a sewer overflow, is released into a body of water.",
  "section": "sewer",
  "source_url": "https://www.mwra.com/harbor/html/bostonharborproject.htm"
 },
 {
  "term": "overhead catenary",
  "aka": "overhead wire",
  "category": "Transit",
  "definition": "A wire strung above the track that a train touches with a pantograph or trolley pole to draw electricity. Boston's Green Line uses it.",
  "section": "transit",
  "source_url": "https://www.mass.gov/doc/appendix-b-mbta-system-description/download"
 },
 {
  "term": "override",
  "aka": "Proposition 2½ override",
  "category": "Money",
  "definition": "A voter-approved permanent increase in a Massachusetts town's levy limit, passed by majority vote.",
  "section": "money",
  "source_url": "https://www.mass.gov/doc/chapter-3-proposition-2-12/download"
 },
 {
  "term": "ozonation",
  "aka": "ozone disinfection",
  "category": "Water",
  "definition": "Disinfecting water with ozone gas, which kills microbes including tough parasites such as Cryptosporidium and Giardia.",
  "section": "water",
  "source_url": "https://www.mwra.com/node/1437"
 },
 {
  "term": "P25",
  "aka": "Project 25",
  "category": "Emergency",
  "definition": "A digital radio standard meant to let public safety radios from different makers work together.",
  "section": "alarm",
  "source_url": "https://www.apcointl.org/spectrum-management/resources/interoperability/p25/"
 },
 {
  "term": "Pay-as-you-throw",
  "aka": "",
  "category": "Waste",
  "definition": "Charging households by how much they throw away, for example through designated bags or bins that weigh food waste.",
  "section": "waste",
  "source_url": "https://en.wikipedia.org/wiki/Recycling_in_South_Korea"
 },
 {
  "term": "Peak demand",
  "aka": "peak",
  "category": "Power",
  "definition": "The highest amount of electricity used at one moment, which the grid must be built to meet. New England's record is 28,130 MW.",
  "section": "grid",
  "source_url": "https://iso-ne.com/about/key-stats"
 },
 {
  "term": "Pedestrian recall",
  "aka": "",
  "category": "Traffic",
  "definition": "A setting that brings up the walk signal every cycle automatically, so the push button has no effect on timing.",
  "section": "signals",
  "source_url": "https://www.wgbh.org/news/local/2020-01-15/a-look-at-bostons-traffic-signal-system"
 },
 {
  "term": "Phase",
  "aka": "",
  "category": "Traffic",
  "definition": "A timed block of the signal cycle that serves one set of movements that can safely go together.",
  "section": "signals",
  "source_url": "https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter6.htm"
 },
 {
  "term": "Phase I / Phase II",
  "aka": "wireless 911 phases",
  "category": "Emergency",
  "definition": "US stages for wireless 911 location: Phase I gives the cell tower, Phase II adds the caller's estimated coordinates.",
  "section": "alarm",
  "source_url": "https://nena.org/page/911statistics"
 },
 {
  "term": "Phosphor",
  "aka": "",
  "category": "Light",
  "definition": "A coating in a white LED that turns some of its blue light into yellow so the mix looks white. When it fails, the light can look purple.",
  "section": "light",
  "source_url": "https://en.wikipedia.org/wiki/2020s_purpling_of_streetlights"
 },
 {
  "term": "Photocell",
  "aka": "photocontrol",
  "category": "Light",
  "definition": "A small light sensor that switches a streetlight on at dusk and off at dawn.",
  "section": "light",
  "source_url": "https://en.wikipedia.org/wiki/Street_light"
 },
 {
  "term": "Pneumatic waste system",
  "aka": "AVAC",
  "category": "Waste",
  "definition": "Underground tubes that use air to move trash from buildings to a central collection point, as on New York's Roosevelt Island since 1974.",
  "section": "waste",
  "source_url": "https://untappedcities.com/2020/04/09/inside-roosevelt-islands-futuristic-pneumatic-tube-trash-system/"
 },
 {
  "term": "point source",
  "aka": "",
  "category": "Rules",
  "definition": "A single identifiable source of pollution, such as a pipe, which the US Clean Water Act requires to have a permit.",
  "section": "primer",
  "source_url": "https://www.epa.gov/laws-regulations/history-clean-water-act"
 },
 {
  "term": "poor (bridge condition)",
  "aka": "",
  "category": "Roads",
  "definition": "A US bridge whose lowest-rated deck, superstructure, substructure or culvert scores 4 or less on a 0-9 scale.",
  "section": "roads",
  "source_url": "https://www.fhwa.dot.gov/bridge/britab.cfm"
 },
 {
  "term": "Preemption",
  "aka": "Emergency vehicle preemption",
  "category": "Traffic",
  "definition": "Interrupting a signal's normal operation to give an immediate green to an emergency vehicle or clear a railroad crossing.",
  "section": "signals",
  "source_url": "https://www.marc.org/sites/default/files/2023-03/OGL-traffic-signal-basics.pdf"
 },
 {
  "term": "Premark",
  "aka": "white paint",
  "category": "History",
  "definition": "The white paint or stakes an excavator puts down to show where digging will happen, before notifying Dig Safe so utilities can mark their lines.",
  "section": "stack",
  "source_url": "https://www.mass.gov/guides/about-dig-safe"
 },
 {
  "term": "pressure zone",
  "aka": "",
  "category": "Water",
  "definition": "A section of a water system or tall building kept within a set pressure range by elevation, pumps or valves. In high-rises a zone typically spans 9 to 10 floors.",
  "section": "tall",
  "source_url": "https://www.phcppros.com/articles/1899-high-rise-plumbing-design-and-plumbing-codes"
 },
 {
  "term": "pressure-reducing valve",
  "aka": "PRV",
  "category": "Water",
  "definition": "A valve that lowers water pressure to a safe level for the pipes and fixtures downstream.",
  "section": "tall",
  "source_url": "https://www.csemag.com/design-basics-for-booster-pumps-in-high-rise-buildings/"
 },
 {
  "term": "Pretimed control",
  "aka": "Fixed-time control",
  "category": "Traffic",
  "definition": "Signal operation where every phase gets a set amount of time every cycle regardless of traffic.",
  "section": "signals",
  "source_url": "https://nap.nationalacademies.org/read/22097/chapter/14"
 },
 {
  "term": "primary treatment",
  "aka": "",
  "category": "Waste",
  "definition": "The first stage of sewage treatment, where solids settle out of wastewater.",
  "section": "primer",
  "source_url": "https://www.mwra.com/harbor/html/bostonharborproject.htm"
 },
 {
  "term": "Producer responsibility organization",
  "aka": "PRO",
  "category": "Waste",
  "definition": "A nonprofit that collects fees from producers under an EPR law and runs or funds the recycling system. Circular Action Alliance is one in the US.",
  "section": "waste",
  "source_url": "https://www.lightnowblog.com/2025/12/7-states-have-epr-packaging-laws-5-more-assessing-need"
 },
 {
  "term": "Proposition 2½",
  "aka": "Prop 2½",
  "category": "Money",
  "definition": "A 1980 Massachusetts law that caps how much property tax a city or town can raise, effective FY1982.",
  "section": "money",
  "source_url": "https://www.mass.gov/doc/chapter-3-proposition-2-12/download"
 },
 {
  "term": "PSAP",
  "aka": "public safety answering point",
  "category": "Emergency",
  "definition": "The call center that answers 911 calls.",
  "section": "alarm",
  "source_url": "https://nena.org/page/911statistics"
 },
 {
  "term": "psi",
  "aka": "pounds per square inch",
  "category": "Water",
  "definition": "A unit of water pressure. Each foot of water height adds about 0.433 psi.",
  "section": "water",
  "source_url": "https://www.phcppros.com/articles/1899-high-rise-plumbing-design-and-plumbing-codes"
 },
 {
  "term": "Right turn on red",
  "aka": "RTOR",
  "category": "Traffic",
  "definition": "A US rule allowing drivers to turn right after stopping at a red light unless a sign prohibits it.",
  "section": "signals",
  "source_url": "https://sauerburger.org/rtor.html"
 },
 {
  "term": "Ring and barrier",
  "aka": "NEMA ring-barrier diagram",
  "category": "Traffic",
  "definition": "The US way of diagramming phases: two rings of conflicting movements run side by side, and barriers keep conflicting movements in different rings from ever being timed together.",
  "section": "signals",
  "source_url": "https://nap.nationalacademies.org/read/22097/chapter/14"
 },
 {
  "term": "safe yield",
  "aka": "",
  "category": "Water",
  "definition": "The amount of water a supply can reliably deliver every day, even through a long drought.",
  "section": "water",
  "source_url": "https://www.mwra.com/node/1491"
 },
 {
  "term": "Sanitary landfill",
  "aka": "",
  "category": "Waste",
  "definition": "An engineered disposal site where waste is compacted and covered with soil, rather than left exposed as in an open dump.",
  "section": "waste",
  "source_url": "https://www.epa.gov/landfills/municipal-solid-waste-landfills"
 },
 {
  "term": "Secondary network",
  "aka": "network system",
  "category": "Power",
  "definition": "A downtown underground grid in which many transformers feed one shared low-voltage mesh, so one failure does not cause an outage.",
  "section": "grid",
  "source_url": "https://en.wikipedia.org/wiki/Network_protector"
 },
 {
  "term": "secondary treatment",
  "aka": "",
  "category": "Waste",
  "definition": "A second stage of sewage treatment, where bacteria break down dissolved organic pollution.",
  "section": "primer",
  "source_url": "https://www.mwra.com/harbor/html/bostonharborproject.htm"
 },
 {
  "term": "selective router",
  "aka": "",
  "category": "Emergency",
  "definition": "The phone-network switch in legacy 911 that sends each call to the correct PSAP.",
  "section": "alarm",
  "source_url": "https://www.fcc.gov/node/267074"
 },
 {
  "term": "Sensing line",
  "aka": "control line",
  "category": "Gas and steam",
  "definition": "A small pipe that tells a gas regulator the downstream pressure, so it knows whether to open or close.",
  "section": "gas-steam",
  "source_url": "https://www-s.ntsb.gov/news/press-releases/Pages/NR20190924.aspx"
 },
 {
  "term": "service line",
  "aka": "",
  "category": "Water",
  "definition": "The pipe that connects a building to the water main under the street.",
  "section": "water",
  "source_url": "https://www.bhfs.com/insight/leading-the-way-new-epa-rule-gives-10-years-to-replace-lead-drinking-water-service-lines/"
 },
 {
  "term": "Siamese connection",
  "aka": "fire department connection (FDC)",
  "category": "Water",
  "definition": "A fitting with at least two inlets on a building's exterior where fire engines pump water into its standpipes or sprinklers.",
  "section": "tall",
  "source_url": "https://blog.qrfs.com/54-what-is-a-siamese-connection/"
 },
 {
  "term": "Signal head",
  "aka": "",
  "category": "Traffic",
  "definition": "The housing on a pole or mast arm that holds a signal's red, yellow and green lights.",
  "section": "signals",
  "source_url": "https://www.marc.org/sites/default/files/2023-03/OGL-traffic-signal-basics.pdf"
 },
 {
  "term": "Single-stream recycling",
  "aka": "",
  "category": "Waste",
  "definition": "A system where paper, cans, bottles and containers all go into one bin and are separated later at a sorting plant.",
  "section": "waste",
  "source_url": "http://resource-recycling.com/plastics/2024/01/10/residential-recycling-report-estimates-21-recovery-rate/"
 },
 {
  "term": "slow zone",
  "aka": "speed restriction",
  "category": "Transit",
  "definition": "A stretch of track where trains must slow down because the track or its supports are in poor condition.",
  "section": "transit",
  "source_url": "https://www.cbsnews.com/amp/boston/news/mbta-slow-zones-red-line-commute"
 },
 {
  "term": "small cell",
  "aka": "",
  "category": "Data and telecom",
  "definition": "A low-power cell site, often on a streetlight or utility pole, that adds mobile capacity over a short range.",
  "section": "311",
  "source_url": "https://www.everycrsreport.com/files/2019-02-25_LSB10265_ddf589286a891d1b2d70884fa4eded9c3be66932.html"
 },
 {
  "term": "smart city",
  "aka": "",
  "category": "Data and telecom",
  "definition": "A city that uses sensors, data and software to manage services like traffic, energy and water.",
  "section": "primer",
  "source_url": "https://www.archdaily.com/939152/sidewalk-labs-cancels-quayside-smart-city-project-in-toronto"
 },
 {
  "term": "Snow emergency",
  "aka": "",
  "category": "Streets",
  "definition": "An official city declaration that bans parking on main roads so plows can clear them; in Boston, cars left there are ticketed and towed.",
  "section": "streets",
  "source_url": "https://boston.gov/snow-cars"
 },
 {
  "term": "Space saver",
  "aka": "",
  "category": "Streets",
  "definition": "An object such as a chair or cone placed in a shoveled parking spot to claim it. Boston tolerates them only during a declared snow emergency and for 48 hours after, and bans them in the South End and Bay Village.",
  "section": "streets",
  "source_url": "https://boston.gov/snow-cars"
 },
 {
  "term": "SPaT",
  "aka": "Signal phase and timing",
  "category": "Traffic",
  "definition": "A data message from a signal telling connected vehicles which light is showing and when it will change.",
  "section": "signals",
  "source_url": "https://www.ite.org/technical-resources/topics/standards/ntcip-1202-v04-actuated-signal-control-asc/"
 },
 {
  "term": "Split",
  "aka": "",
  "category": "Traffic",
  "definition": "The share of the cycle given to one phase, usually including its yellow and all-red time.",
  "section": "signals",
  "source_url": "https://ops.fhwa.dot.gov/publications/fhwahop08024/chapter6.htm"
 },
 {
  "term": "Spot network",
  "aka": "",
  "category": "Power",
  "definition": "Two or more transformers dedicated to a single large customer, for extra reliability.",
  "section": "grid",
  "source_url": "https://en.wikipedia.org/wiki/Network_protector"
 },
 {
  "term": "standpipe",
  "aka": "fire standpipe",
  "category": "Water",
  "definition": "A vertical pipe in a larger building that feeds hose valves firefighters connect to.",
  "section": "tall",
  "source_url": "https://blog.qrfs.com/54-what-is-a-siamese-connection/"
 },
 {
  "term": "Steam stack",
  "aka": "",
  "category": "Gas and steam",
  "definition": "The orange-and-white tube placed over a manhole to vent steam above people and traffic.",
  "section": "gas-steam",
  "source_url": "https://en.wikipedia.org/wiki/New_York_City_steam_system"
 },
 {
  "term": "steel frame",
  "aka": "skeleton frame",
  "category": "Rules",
  "definition": "A grid of metal columns and beams that carries a building's weight, so the outer walls no longer have to.",
  "section": "primer",
  "source_url": "https://www.pbs.org/wgbh/buildingbig/for_siemens/basics/sky_basics.html"
 },
 {
  "term": "storm surge barrier",
  "aka": "",
  "category": "Climate",
  "definition": "A movable gate across a river or estuary that closes to keep exceptionally high tides out of a city.",
  "section": "primer",
  "source_url": "https://www.gov.uk/guidance/the-thames-barrier"
 },
 {
  "term": "street opening moratorium",
  "aka": "Moratorium Street",
  "category": "Roads",
  "definition": "A rule barring utility digging in a recently rebuilt or resurfaced street, five years in Cambridge, Massachusetts, except in emergencies.",
  "section": "roads",
  "source_url": "https://www.cambridgema.gov/-/media/Files/publicworksdepartment/streetmaintenance/revisedspofregulationsseptember2015.pdf"
 },
 {
  "term": "Street sweeping program",
  "aka": "",
  "category": "Streets",
  "definition": "Scheduled mechanical cleaning of curbs, enforced with posted parking restrictions, tickets and tows.",
  "section": "streets",
  "source_url": "https://www.boston.gov/departments/public-works/all-about-street-sweeping"
 },
 {
  "term": "streetcar suburb",
  "aka": "",
  "category": "Transit",
  "definition": "A neighborhood built along streetcar lines, letting people live farther from work.",
  "section": "primer",
  "source_url": "https://ethw.org/Milestones:Richmond_Union_Passenger_Railway,_1888"
 },
 {
  "term": "strong-mayor system",
  "aka": "mayor-council",
  "category": "Government",
  "definition": "A city government in which an elected mayor runs the administration and proposes the budget, with the council acting mainly as a check.",
  "section": "who",
  "source_url": "https://www.dotnews.com/2025/06/11/48b-budget-set-wu-says-boston-can-weather-moment/"
 },
 {
  "term": "subgrade",
  "aka": "",
  "category": "Roads",
  "definition": "The native soil a road is built on.",
  "section": "roads",
  "source_url": "https://practical.engineering/blog/2020/8/31/how-do-potholes-work"
 },
 {
  "term": "Sump",
  "aka": "",
  "category": "History",
  "definition": "A low pit where water collects in a tunnel until pumps switch on at a set level. New York's subway has 300 pump rooms.",
  "section": "stack",
  "source_url": "https://ny1.com/nyc/all-boroughs/transit/2018/04/17/mta-subway-pump-system-neverending-battle-to-keep-water-from-overwhelming-subways"
 },
 {
  "term": "Thames Tideway Tunnel",
  "aka": "super sewer",
  "category": "Sewer",
  "definition": "A 25 km storage tunnel under the Thames in London that intercepts 34 of the worst combined sewer overflows, opened in 2025.",
  "section": "sewer",
  "source_url": "https://en.wikipedia.org/wiki/Thames_Tideway_Tunnel"
 },
 {
  "term": "third rail",
  "aka": "",
  "category": "Transit",
  "definition": "A powered rail beside the running rails that a train touches with a sliding shoe to draw electricity. Boston's Red and Orange Lines use it.",
  "section": "transit",
  "source_url": "https://www.mass.gov/doc/appendix-b-mbta-system-description/download"
 },
 {
  "term": "Time-of-day plan",
  "aka": "timing plan",
  "category": "Traffic",
  "definition": "A signal timing pattern switched by the clock, such as morning, off-peak, evening and overnight. Boston uses four default plans.",
  "section": "day",
  "source_url": "https://www.wgbh.org/news/local/2020-01-15/a-look-at-bostons-traffic-signal-system"
 },
 {
  "term": "traction power substation",
  "aka": "",
  "category": "Transit",
  "definition": "A facility that converts grid power into the direct current trains run on.",
  "section": "transit",
  "source_url": "https://www.mass.gov/doc/appendix-b-mbta-system-description/download"
 },
 {
  "term": "Traffic management center",
  "aka": "TMC",
  "category": "Traffic",
  "definition": "The control room where engineers watch cameras and adjust signal timing across a city.",
  "section": "signals",
  "source_url": "https://www.wgbh.org/news/local/2020-01-15/a-look-at-bostons-traffic-signal-system"
 },
 {
  "term": "Transit signal priority",
  "aka": "TSP",
  "category": "Traffic",
  "definition": "A small timing adjustment, such as holding a green a few seconds longer, to help an approaching bus.",
  "section": "signals",
  "source_url": "https://www.wbur.org/news/2025/02/03/mbta-boston-buses-transit-signal-priority-technology-newsletter"
 },
 {
  "term": "Transmission",
  "aka": "",
  "category": "Power",
  "definition": "High-voltage lines that move power long distances from plants to substations. In New England this means 115 kV and above.",
  "section": "grid",
  "source_url": "https://iso-ne.com/about/key-stats"
 },
 {
  "term": "Transport for London",
  "aka": "TfL",
  "category": "Government",
  "definition": "The body, created in 2000 under the Mayor of London, that runs London's Underground, buses, trams, main roads and congestion charge.",
  "section": "who",
  "source_url": "https://en.wikipedia.org/wiki/Transport_for_London"
 },
 {
  "term": "trip stop",
  "aka": "",
  "category": "Transit",
  "definition": "A trackside device that stops a train automatically if it runs a red signal.",
  "section": "transit",
  "source_url": "https://www.mass.gov/doc/appendix-b-mbta-system-description/download"
 },
 {
  "term": "urban heat island",
  "aka": "",
  "category": "Climate",
  "definition": "The effect that makes cities hotter than surrounding countryside, because pavement and roofs absorb sun and there is less shade.",
  "section": "climate",
  "source_url": ""
 },
 {
  "term": "urban renewal",
  "aka": "",
  "category": "Rules",
  "definition": "Mid-20th-century government programs that cleared neighborhoods labeled as blighted and redeveloped them, often displacing residents.",
  "section": "primer",
  "source_url": "https://www.history.com/articles/interstate-highway-system-infrastructure-construction-segregation"
 },
 {
  "term": "UV disinfection",
  "aka": "ultraviolet treatment",
  "category": "Water",
  "definition": "Passing water under ultraviolet light so microbes such as Cryptosporidium cannot reproduce.",
  "section": "water",
  "source_url": "https://www.mwra.com/node/1437"
 },
 {
  "term": "variance",
  "aka": "",
  "category": "Rules",
  "definition": "Permission from a local board to build something that does not meet the zoning rules.",
  "section": "rules",
  "source_url": ""
 },
 {
  "term": "Vision Zero",
  "aka": "",
  "category": "Roads",
  "definition": "A road-safety policy that aims to eliminate all traffic deaths and serious injuries. Boston adopted it in 2015 with a 2030 target.",
  "section": "roads",
  "source_url": "https://media.wbur.org/wp/2026/07/Resolution-recommitting-the-City-of-Boston-to-Vision-Zero-2030.pdf"
 },
 {
  "term": "Waste-to-energy",
  "aka": "WtE; energy-from-waste",
  "category": "Waste",
  "definition": "Burning trash in controlled plants to produce electricity and, in places like Copenhagen, heat for homes.",
  "section": "waste",
  "source_url": "https://www.power-technology.com/projects/amager-bakke-waste-energy-plant/"
 },
 {
  "term": "watershed",
  "aka": "",
  "category": "Water",
  "definition": "The land that drains rain and snowmelt into a particular river, lake or reservoir.",
  "section": "water",
  "source_url": "https://www.mwra.com/node/1437"
 },
 {
  "term": "WEA",
  "aka": "Wireless Emergency Alerts",
  "category": "Emergency",
  "definition": "Government warnings broadcast from cell towers to phones in an area, with no app needed.",
  "section": "alarm",
  "source_url": "https://www.weather.gov/news/062422-wea-10yr"
 },
 {
  "term": "z-axis",
  "aka": "vertical location",
  "category": "Emergency",
  "definition": "The vertical dimension of a caller's location, used to find the right floor in a tall building.",
  "section": "alarm",
  "source_url": "https://www.tlp.law/2025/04/03/fcc-adopts-fnprm-aimed-at-improving-911-location-accuracy/"
 },
 {
  "term": "zoning",
  "aka": "",
  "category": "Rules",
  "definition": "Local rules that set what kinds of buildings and uses are allowed on each piece of land, and how large they may be.",
  "section": "rules",
  "source_url": ""
 }
]