Live SteamSteam available directly from a boiler under full pressure.
Livestock guzzlerA watering system for cattle and other livestock that maintains a set water level as water is used.
Livestock watering areaWater used for livestock watering, feed lots, dairy operations, fish farming, and other on-farm needs.
LoadCommissions charged on the purchase or sale of mutual fund units.
Load AnalysisAssessing and quantifying the discrete components that comprise a load. This analysis often includes time of day or season as a variable.
Load controlThe process of managing demand requirements in order to achieve a desired load pattern.
Load Duration CurveA curve that displays load values on the horizontal axis in descending order of magnitude against the percent of time (on the vertical axis) that the load…
Load factorThe ratio of average energy demand (load) to maximum demand (peak load) during a specific period.
Load ForecastAn estimate of power demand at some future period.
Load LevelingThe deferment of certain loads to limit electrical power demand, or the production of energy during off-peak periods for storage and use during peak…
Load pocketAn area often dependent on transmission for reliable electric system operation because the area’s load often exceeds the generation in the area.
Load Profile or ShapeA curve on a chart showing power (kW) supplied (on the horizontal axis) plotted against time of occurrence (on the vertical axis) to illustrate the…
Load SheddingTurning off or disconnecting loads to limit peak demand.
Load ShiftingA load management objective that moves loads from on-peak periods to off-peak periods.
Load-serving entity (LSE)(LSE)Any entity, including a load aggregator or power marketer, that serves end-users within a control area and has been granted the authority or has an…
LoamA soil consisting of an easily crumbled mixture of clay, silt, and sand.
Local distribution company (LDC)(LDC)Any firm, other than a natural gas pipeline, engaged in the transportation or local distribution of natural gas and its sale to customers that will…
Local Solar TimeA system of astronomical time in which the sun crosses the true north-south meridian at 12 noon, and which differs from local time according to longitude…
Locatable MineralsMinerals or materials subject to disposal and development through the Mining Law of 1872 (as amended).
Location Efficient MortgageA lending program that allows homebuyers to borrow more money based on the transportation cost savings of living near mass transit.
Locational installed capacityInstalled capacity in a specific location (e.g., New York City), rather than in a broader area (e.g., anywhere in New York State).
Locational marginal priceThe market-clearing price for electricity at the location the energy is delivered or received.
LODEA mineralized ledge, vein or mineral deposit in place.
Lode mining claimA claim based on the presumption that the valuable mineral is a part of a bed-rock lode, vein, stockwork, stratum, or intrusion and is not dominantly a…
LoessA group of windblown soils, largely comprising silt, weakly cemented by calcite.
Log chokerA length of cable or chain that is wrapped around a log or harvested tree to secure the log to the winch cable of a skidder or to an overhead cable…
Log LawIn reference to a wind energy conversion system, the wind speed profile in which wind speeds increase with the logarithmic of the height of the wind…
Logging residuesThe unused portion of wood and bark left on the ground after harvesting merchantable wood.
longA term signifying ownership of securities. "I am long 100 XYZ," means that the speaker owns 100 shares of XYZ.
Long TonA unit that equals 20 long hundredweight or 2,240 pounds. Used mainly in England.
Long-term productivityThe capacity of a site to support forest ecosystems over generations of humans and trees as measured against some defined reference.
Loop flowUnintended or unscheduled flow of electricity through a line or system.
Loose Fill InsulationInsulation made from rockwool fibers, fiberglass, cellulose fiber, vermiculite or perlite minerals, and composed of loose fibers or granules can be…
Loss of Load Probability (LOLP)(LOLP)A measure of the probability that a system demand will exceed capacity during a given period; often expressed as the estimated number of days over a long…
LossesEnergy (kilowatt-hours) and power (kilowatts) lost in the operation of an electric system, principally as waste heat in electrical conductors and…
Losses (Energy)A general term applied to the energy that is converted to a form that can not be effectively used (lost) during the operation of an energy producing…
Lot Areaarea is the total square footage of horizontal area included within the property lines.
Low Btu GasA fuel gas with a heating value between 90 and 200 Btu per cubic foot.
Low Flush ToiletA toilet that uses less water than a standard one during flushing, for the purpose of conserving water resources.
Low Impact Development (LID)An approach to environmentally friendly land use planning. It includes a suite of landscaping and design techniques that attempt to maintain the natural…
Low-e windowsLow-emittance (Low-E) refers to very thin coatings on a window primarily used to reduce heat flow through the window.
Low-Emissivity Windows & (Window) FilmsEnergy-efficient windows that have a coating or film applied to the surface of the glass to reduce heat transfer through the window.
Low-income populationPersons whose average family income is below the poverty line. The poverty line takes into account family size and age of individuals in the family.
Low-level magnetic fieldsFields of force that are generated whenever electric current flows. The sun's average large-scale magnetic field, and the Earth's, exhibit a north and a…
Low-Pressure Sodium LampA type of lamp that produces light from sodium gas contained in a bulb operating at a partial pressure of 0.13 to 1.3 Pascal.
Lower (Net) Heating ValueThe lower or net heat of combustion for a fuel that assumes that all products of combustion are in a gaseous state. (See Net Heating Value below.)
Lower Heating Value (LHV)(LHV)The heating value is the amount of heat released during the combustion of a specific substance, usually a fuel or food.
lower heating value (LLV)(LLV)The heat produced by combusting one unit of a substance, at atmospheric pressure under conditions such that all water in the products remains in the form…
LumenThe cavity or channel within a tube or tubular organ such as a blood vessel or the intestine.
Lumens/Watt (lpw)A measure of the efficacy (efficiency) of lamps. It indicates the amount of light (lumens) emitted by the lamp for each unit of electrical power (Watts)…
LuminaireA complete lighting unit consisting of a lamp(s), housing, and connection to the power circuit.
LuminanceThe physical measure of the subjective sensation of brightness; measured in lumens.
LuxThe unit of illuminance equivalent to 1lumen per square meter.
MaarA volcanic crater that is produced by an explosion in an area of low relief, is generally more or less circular, and often contains a lake, pond, or marsh.
Macrophyte (aquatic)An aquatic plant that is large enough to be observed with the naked eye. It grows in or near water.
Mafic (or maphic)A term used to describe an igneous rock that has a large percentage of dark-colored minerals such as amphibole, pyroxene, and olivine.
MagmaMolten or partially molten rock at temperatures ranging from 1,260 F to 2,880 F (700 C to 1600 C).
Magnetic BallastA type of florescent light ballast that uses a magnetic core to regulate the voltage of a florescent lamp.
Maintenance areaAny geographic region of the United States previously designated nonattainment pursuant to the CAA Amendments of 1990 and subsequently redesignated to…
Major sourceA source that emits, or has the potential to emit, a pollutant regulated under the Clean Air Act in excess of a specified rate in a nonattainment area.
Make-Up AirAir brought into a building from outside to replace exhaust air.
MammalsA group of air-breathing animals whose skin is more or less covered with hair or fur and who have mammary glands.
Management activitiesPlanned activities initiated by land managers to meet the desired future condition for an area.
Management areaManagement areas are specific geographical areas defined by a forest plan. Each management area has a set of objectives and a management prescription…
Management indicator speciesSpecies selected as ecological indicators. The welfare of a management indicator species is presumed to be an indicator of the welfare of other species…
Management planA plan guiding overall management of an area administered by a federal or state agency.
mannanThe polymer of mannose with a repeating unit of C6H10O5. Can be hydrolyzed to mannose. (Source: Voet, D.; Voet, J. G. Biochemistry.
mannoseA hexose component of many polysaccharides, occasionally used as a carbohydrate source in plant tissue culture media.
ManoA stone with a flat side that was primarily held in one's hand or hands and used to grind edible substances, typically corn, grains, and nut meats.
MantleThe main bulk of the Earth, between the crust and core, ranging from depths of about 40 to 3,480 kilometers.
Mantle hot spotA region of continental or oceanic crust below which a mantle plume causes melting of the overlying crust, resulting in a broad regional topographic swell…
Manual JThe standard method for calculating residential cooling loads developed by the Air-Conditioning and Refrigeration Institute (ARI) and the Air Conditioning…
Margin requirementThe margin requirement is the minimum amount the Federal Reserve, in Regulation T, requires you to deposit in a margin account before you can trade…
Marginal CostThe cost of producing one additional unit of a product.
Marginal electric generating unitIn organized wholesale markets, the price of the marginal source of electricity usually sets the price of the unit providing the next increment or…
Mark-to-marketAdjustment of the book value or collateral value of a security – including a security such as a multiyear contract – to reflect current market value…
MarketTraditionally, a securities market was a place - such as the New York Stock Exchange (NYSE) - where members met to buy and sell securities.
Market capitalizationValue of a corporation as determined by the market price of its issued and outstanding securities.
Market concentrationA measure, usually an estimate, of the market share of a participant or groups of participant in the overall market or a submarket (a given region…
Market liquidityThe ease, or lack thereof, with which a buyer can buy or a seller can sell at a prevailing price in a marketplace.
Market participantA market buyer or a market seller, or both, that meets reasonable creditworthiness standards established by the market operator.
Market powerThe ability of any market participant with a large market share to significantly control or affect price by withholding production from the market…
Market structureThe rules, mechanisms and processes, under which a market operates to form prices, provide benefits and introduce risks to participants, and ultimately…
MarshAn area of low-lying wetlands dominated by grasslike plants.
mashA mixture of grain and other ingredients with water to prepare wort for brewing operations.
Masonry StoveA type of heating appliance similar to a fireplace, but much more efficient and clean burning.
Mass Burn FacilityA type of municipal solid waste (MSW) incineration facility in which MSW is burned with only minor presorting to remove oversize, hazardous, or explosive…
mass closure (%)The percent by weight of the total samples extracted from the biomass sample compared to the weight of the original sample.
Massachusetts Sustainable Design RoundtableCreated by the Executive Office of Energy and Environmental Affairs and the Division of Capital Asset Management the Roundtable explores ways in which the…
MassGISThe Commonwealth's Office of Geographic and Environmental Information, within the Massachusetts Executive Office of Energy and Environmental Affairs…
Master PlanThe term has two meanings: 1) a permit type issued to large residential or commercial buildings that sets a building-wide standard for future changes that…
Maximum Contaminant Level (MCL)(MCL)The highest level of a contaminant that is allowed in drinking water. MCLs ensure that drinking water does not pose either a short-term or long-term…