continuous cultureA suspension culture continuously supplied with nutrients by the inflow of fresh medium. The culture volume is normally constant.
continuous fermentationA process in which cells or micro-organisms are maintained in culture in the exponential growth phase by the continuous addition of fresh medium that is…
continuous variationVariation where individuals cannot be classified as belonging to one of a set of discrete classes.
Continuous-flow irrigationSystem of irrigation water delivery where each irrigator receives their allotted quantity of water at a continuous rate.
Continuum Storm (CTM)In solar-terrestrial terms, general term for solar noise lasting for hours and sometimes days.
Contour ditchIrrigation ditch laid out approximately on the contour.
Contour farmingSystem of farming used for erosion control and moisture conservation whereby field operations are performed approximately on the contour.
Contour floodingMethod of irrigation by flooding from contour ditches.
Contour mapTopographic map that portrays relief or elevation differences by the use of lines (contours) indiciating equal elevation.
Contour plowingPlowing done in accordance with the natural outline or shape of the land by keeping the furrows or ditches at the same elevation as much as possible to…
Contour strip farmingA kind of contour farming in which row crops are planted in strips, between alternating strips of close-growing, erosion resistant forage (grass, grain…
Contract rateThe repayment or water service rate set forth in a contract to be paid by a district to the United States.
Contracted weirThe crest and sides of a retangular weir are far enough from the bottom and sides of the channel so that their effect on flow is negligible.
Contraction jointContraction joints are joints placed in concrete to provide for volumetric shrinkage of a monolithic unit or movement between monolithic units.
contrail (condensation trail)A cloudlike streamer frequently seen forming behind aircraft flying in clear, cold, humid air.
ContrastThe difference between the brightness of an object compared to that of its immediate background.
Contrast levelA description of the relative amount of visual contrast resulting from a change in the visible landscape.
Control areaAn electric power system or combination of electric power systems to which a common automatic control scheme is applied in order to: Match, at all times…
Control elementsDNA sequences in genes that interact with regulatory proteins (such as transcription factors) to determine the rate and timing of expression of the genes…
Control jointControl joints are joints placed in concrete to provide for control of initial shrinkage stresses and cracks of monolithic units.
Control plotA plot in which no vegetation will be cut and natural succession will occur. A control plot serves as a baseline to compare other treatments (Early, Mid…
Control PointsHorizontal and Vertical: Small monuments securely embedded in the surface of the dam. Any movement of the monument indicates a movement in the dam itself.
Control structure (control house)Concrete portion of an outlet works, located at the downstream end of the tunnel or conduit, housing the control (regulation) gates.
Controlled EnvironmentA closed environment in which parameters, such as light, temperature, relative humidity and sometimes the partial gas pressure (and possibly its…
controlling elementIn eukaryotes, transposons which affect the activity of known genes. This can occur as a result of the integration within, or close to a gene, thereby…
ConvectionThe movement of matter due to changes in temperature and density. Warm material rises because it is less dense (lighter) and cool material sinks because…
Convection cloudConvection cloud Cumuliform cloud which forms in the atmosphere as a result of convection. Such clouds are also called clouds of vertical development.
Convective Boundary LayerThe unstable boundary layer that forms at the surface and grows upward through the day as the ground is heated by the sun and convective currents transfer…
Convective CloudsThe vertically developed family of clouds are cumulus and cumulonimbus. The height of their bases range from as low as 1,000 feet to a bit more than…
Convective Condensation Level(abbrev. CCL)- The level in the atmosphere to which an air parcel, if heated from below, will rise dry adiabatically, without becoming colder than its…
convective condensation level (CCL)(CCL)The level above the surface marking the base of a cumuliform cloud that is forming due to surface heating and rising thermals.
Convective Inhibition(CIN or B-) - A numerical measure of the strength of "capping," typically used to assess thunderstorm potential.
Convective Outlook(sometimes called AC) - A forecast containing the area(s) of expected thunderstorm occurrence and expected severity over the contiguous United States…
Convective OverdevelopmentConvection that covers the sky with clouds, thereby cutting off the sunshine that produces convection.
Convective TemperatureThe approximate temperature that the air near the ground must warm to in order for surface-based convection to develop, based on analysis of a sounding.
Convective ZoneThe Sun is made up of different layers. From its center outward, the Sun’s layers include the core, the convective zone, the radiative zone, the…
Convention on Biological Diversity(Abbreviation: CBD). The inteRNA tional treaty governing the conservation and use of biological resources around the world, that has also called for the…
Conventional forest productsAny commercial roundwood product (boards, dimension lumber, pulp and paper products) except fuelwood.
Conventional PowerPower generation from sources such as petroleum, natural gas, or coal. In some cases, large-scale hydropower and nuclear power generation are considered…
Conventional tillageThe traditional method of farming in which soil is prepared for planting by completely inverting it with a moldboard plow.
ConvergenceIntegration of computing, communications and broadcasting systems.
ConversionThe ability, in some states, to switch your job-based coverage to an individual policy when you lose eligibility for job-based coverage.
Conversion EfficiencyThe amount of energy produced as a percentage of the amount of energy consumed.
ConverterA device for transforming the quality and quantity of electrical energy; also an inverter.
Conveyance LossThe loss of water from a conduit due to leakage, seepage, evaporation, or evapo-transpiration.
Conveyance loss (distribution loss)Loss of water from a channel or pipe during conveyance, including losses due to seepage, leakage, evaporation and transpiration by plants growing in or…
Conveyance system efficiencyThe ratio of the volume of water delivered to users in proportion to the volume of water introduced into the conveyance system.
ConveyorA mechanical apparatus for carrying bulk material from place to place; for example, an endless moving belt or a chain of receptacles.
Cooling CapacityThe quantity of heat that a cooling appliance is capable of removing from a room in one hour.
Cooling Degree DayA value used to estimate interior air cooling requirements (load) calculated as the number of degrees per day (over a specified period) that the daily…
Cooling Degree Days(Abbrev. CDD) - A form of Degree Day used to estimate energy requirements for air conditioning or refrigeration.
Cooling degree days (CDD)(CDD)A measure of cooling energy demand determined by how far a location's temperature averaged above 65 degrees Fahrenheit.
Cooling LoadThat amount of cooling energy to be supplied (or heat and humidity removed) based on the sensible and latent loads.
Cooling PondA body of water used to cool the water that is circulated in an electric power plant.
Cooling TowerA structure used to cool power plant water; water is pumped to the top of the tubular tower and sprayed out into the center, and is cooled by evaporation…
cooperating programA program or agency supporting a specific ARM effort, such as a field campaign, wherein ARM provides the resources.
Cooperative AgreementFormal document that states the obligations of Reclamation to one or more other parties.
Cooperative electric utilityAn electric utility legally established to be owned by and operated for the benefit of those using its service.
Cooperative ObserverAn individual (or institution) who takes precipitation and temperature observations-and in some cases other observations such as river stage, soil…
coordinate repressionCorrelated regulation of a structural gene within an operon by a molecule that interacts with the operator.
Coordinated operationGenerally, the operation of two or more interconnected electrical systems to achieve greater reliability and economy.
Coordinated Universal Time (UTC)By international agreement, the local time at the prime meridian, which passes through Greenwich, England.
CoordinationThe practice by which two or more interconnected electric power systems augment the reliability of bulk electric power supply by establishing planning and…
Coppice regenerationThe ability of certain hardwood species to regenerate by producing multiple new shoots from a stump left after harvest.
CoproductsThe potentially useful byproducts of ethanol fermentation process.
Coral ReefsLarge living structures of calcium carbonate produced primarily by coral polyps.
CordA stack of wood consisting of 128 cubic feet. A cord has standard dimensions of 4´ x 4´ x 8´ including air space and bark. One cord contains about 1.
Cord (of Wood)A stack of wood 4 feet by 4 feet by 8 feet.
Cord bloodBlood remaining in the umbilical cord immediately following the birth of the baby. It contains a rich concentration of stem cells.
CorduroyA road made of logs laid crosswise on the ground or on other logs.
Core(Kor) the central part of anything, such as the central mass of necrotic matter in a boil.
Core (impervious core or impervious zone)A zone of low permeability material in an embankment dam. Sometimes referred to as "central core," "inclined core," "puddle clay core," and "rolled clay…
Core drillA rotary drill, usually a diamond drill, equipped with a hollow bit and a core lifter.
Core Punch[Slang], a penetration by a vehicle into the heavy precipitation core of a thunderstorm. Core punching is not a recommended procedure for storm spotting.
Core WallA wall of substantial thickness built of impervious material, usually of concrete or asphaltic concrete, in the body of an embankment dam to prevent…
Coriolis ForceA fictitious force used to account for the apparent deflection of a body in motion with respect to the earth, as seen by an observer on the earth.
Corn stoverResidue materials from harvesting corn consisting of the cob, leaves and stalk.
CorneaThe transparent part of the eye that covers the iris and the pupil and allows light to enter the inside.
Corner EffectsA small-scale convergence effect that can be quite severe. It occurs around steep islands and headlands.
CoronaThe outermost layer of the Sun’s outer atmosphere. This halo of ions extends millions of miles into space and consists of a gas that is much thinner…
Corona dischargeElectrical discharge accompanied by ionization of surrounding atmosphere around high-voltage transmission lines, occurring mostly under wet conditions.
Corona/corona noiseThe electrical breakdown of air into charged particles. The phenomenon appears as a bluish-purple glow on the surface of and adjacent to a conductor when…
CoronagraphAn instrument designed to study the Sun’s corona by covering the bright disk of the Sun.
Coronal HoleAn area of the corona that appears dark when viewed in ultraviolet light. They are usually located around the poles of the Sun, but can occur at other…
Coronal Mass Ejection (CME)(CME)A catastrophic expansion of a part of the coronal magnetic field that causes a huge bubble of plasma and magnetic field to erupt from the Sun.
Coronal Rain(Abbrev. CRN) In solar-terrestrial terms, material condensing in the corona and appearing to rain down into the chromosphere as observed at the solar limb…
Coronal TransientsIn solar-terrestrial terms, a general term for short-time-scale changes in the corona, but principally used to describe outward-moving plasma clouds.
Corporate average fuel economy (CAFE)(CAFE)Federal standards enacted in 1975 for fuel economy in motor vehicles. The average of city and highway fuel economy test results weighted by a manufacturer…