Science terms starting with T

597 terms

Terminal structure Portion of spillway downstream from chute, tunnel or conduit, which generally dissipates or stills releases.
terminal transferase An enzyme that catalyses the addition of nucleotides to the 3' end of a DNA molecule.
terminal velocity The constant speed obtained by a falling object when the upward drag on the object balances the downward force of gravity.
terminalization Repelling movement of the centromeres of bivalents in the diplotene stage of the meiotic prophase, that appears to move visible chiasmata toward the ends…
Termination codon Any of three mRNA sequences (UGA, UAG, UAA) that do not code for an amino acid and thus signal the end of protein synthesis. Also known as stop codon.
termination signal In transcription, a nucleotide sequence that specifies RNA chain termination.
terminator 1. A DNA sequence just downstream of the coding segment of a gene, which is recognized by RNA polymerase as a signal to stop synthesizing mRNA. 2.
terminator codon See: stop codon.
terminator gene A specific variety-level genetic use restriction technology. A patented technique.
Terminator region A DNA sequence that signals the end of transcription.
Termite Shield A construction element that inhibits termites from entering building foundations and walls.
Terrace A step-like surface, bordering a valley floor or shoreline, that represents the former position of a floodplain, lake, or sea shore.
Terrain Topographic layout and features of a tract of land or ground.
Terrain Forced Flow An airflow that is modified or channeled as it passes over or around mountains or through gaps in a mountain barrier.
Terrestrial Things of the land.
Terrestrial radiation The total infrared radiation emitted by the Earth and its atmosphere in the temperature range of approximately 200 to 300 Kelvin.
terrigenous derived from land areas. For example, wind-blown dust from desert areas can settle into oceans and form terrigenous sediment on the sea floor.
Territorial communities Populations that function within a particular geographic area.
Tertiary period The earliest period of the Cenozoic era, beginning about 65 million years ago and ending 2.6 million years ago.
tertiary structure The three-dimensional conformation taken up by complete macromolecules as a result of intramolecular interactions, such as hydrogen-bonding.
Tertiary volcanics (Tv) Volcanic rocks deposited during the Tertiary period (between 2.8 and 65 million years ago).
Test pit Pit dug for geologic investigation or inspection and testing of earthwork placement.
test-tube fertilization See: in vitro fertilization.
testcross A cross between a genetically unknown individual and a recessive tester to determine whether the individual in question is heterozygous or homozygous for…
testis (TES-tis) One of two egg-shaped glands inside the scrotum that produce sperm and male hormones. Also called testicle.
testosterone (tes-TOS-ter-own) A hormone that promotes the development and maintenance of male sex characteristics.
Tetracycline An antibiotic drug used to treat infection.
tetrad The four haploid cells formed after the second meiotic division in plants (pollen tetrads) or fungi (ascospores).
tetraploid An organism, or a tissue whose cells contain four haploid sets of chromosome s.
tetrasomic (Noun: tetrasome). Pertaining to a nucleus or an organism with four members of one of its chromosomes, whereas the remainder of its chromosome complement…
tetratype In fungi, a tetrad of spores that contains four different types; e.g. AB, aB, Ab and ab.
Texas Hooker Same as Panhandle Hook - low pressure systems that originate in the panhandle region of Texas and Oklahoma which initially move east and then "hook" or…
Texture The visual manifestations of light and shadow created by the variations in the surface of an object or landscape.
Texture contrasts Visual contrasts between different objects or landscapes resulting from different visual manifestations of the interplay of light and shadow created by…
TGGE Abbreviation for thermal gel gradient electrophoresis.
thallus Plant body without true roots, stems, or leaves.
Thalweg Deepest part of a river channel in a cross section of a river profile. The path of deepest flow. Line connecting the deepest points along a riverbed.
Theodolite An instrument used in surveying to measure horizontal and vertical angles with a small telescope that can move in the horizontal and vertical planes.
Theory most logical explanation of an event that occurs in nature.
therapeutic agent A compound used for the treatment of a disease or for improving the well-being of an organism. Synonyms: pharmaceutical agent, drug.
Therapeutic cloning The potential use of stem cells to grow, in vitro, tissue or organs for use in transplantation.
Therm A unit of heat containing 100,000 British thermal units (Btu).
Thermal A relatively small-scale, rising air current produced when the Earth's surface is heated.
Thermal Balance Point The point or outdoor temperature where the heating capacity of a heat pump matches the heating requirements of a building.
Thermal Belt A zone of high nighttime temperatures (and relatively low humidities) that is often experienced within a narrow altitude range on valley sidewalls…
Thermal Capacitance The ability of a material to absorb and store heat for use later.
Thermal cover Vegetative condition, generally with greater than 70% canopy closure and 40 feet in height, that can significantly ameliorate weather effects such as…
Thermal Efficiency A measure of the efficiency of converting a fuel to energy and useful work; useful work and energy output divided by higher heating value of input fuel…
Thermal Energy The energy developed through the use of heat energy.
Thermal Energy Storage The storage of heat energy during power provider off-peak times at night, for use during the next day without incurring daytime peak electric rates.
Thermal Envelope Houses An architectural design (also known as the double envelope house), sometimes called a "house-within-a-house," that employs a double envelope with a…
thermal gel gradient electrophoresis (Abbreviation: TGGE). A method for separating DNA fragments according to their mobility under increasingly denaturing conditions imposed by heat.
Thermal High Area of high pressure that is shallow in vertical extent and produced primarily by cold surface temperatures.
Thermal inertia The amount of heat energy that must be present in, preserved, or added to a system (in this case, a CSP facility) before it can function as designed.
Thermal Low Area of low pressure that is shallow in vertical extent and produced primarily by warm surface temperatures.
Thermal Mass Materials that store heat.
Thermal Resistance (R-Value) This designates the resistance of a material to heat conduction. The greater the R-value the larger the number.
Thermal resource A facility that produces electricity by using a heat engine to power an electric generator.
Thermal sand Sand used to dissipate heat away from buried electrical cables.
thermal shock Exposure to reduced or increased temperature for a significant period.
Thermal Storage Walls (Masonry or Water) A thermal storage wall is a south-facing wall that is glazed on the outside. Solar heat strikes the glazing and is absorbed into the wall, which conducts…
Thermal stratification The formation of layers of different temperatures in bodies of water. See stratification.
Thermal water A water body (usually a spring or its outflow) that is produced by geothermally heated groundwater.
Thermal Wind It is a theoretical wind that blows parallel to the thickness lines, for the layer considered, analogous to how the geostrophic wind blows parallel to the…
Thermal-electric powerplant A generating plant which uses heat to create steam driven electricity. Such plants may burn coal, gas, oil, wood, waste; or use nuclear, solar, and…
Thermally Driven Circulation A diurnally reversing closed cellular wind current resulting from horizontal temperature contrasts caused by different rates of heating or cooling over…
Thermistor A resistor whose resistance changes with temperature. Because of the known dependence of resistance on temperature, the resistor can be used as a…
Thermochemical Heat and pressure-based chemical reactions that produce energy. Through gasification (heating biomass by partial oxidation to produce synthesis gas) and…
thermochemical conversion The use of heat to change substances chemically to produce energy products.
Thermochemical conversion process Chemical reactions employing heat to produce fuels.
Thermocline A distinct layer of water where rising warm and sinking cold water meet but do not mix.
Thermocouple A device consisting of two dissimilar conductors with their ends connected together.
Thermodynamic Chart A chart containing contours of pressure, temperature, moisture, and potential temperature, all drawn relative to each other such that basic thermodynamic…
Thermodynamic Cycle An idealized process in which a working fluid (water, air, ammonia, etc) successively changes its state (from a liquid to a gas and back to a liquid) for…
Thermodynamic Diagram Used interchangably with Thermodynamic Chart; a chart containing contours of pressure, temperature, moisture, and potential temperature, all drawn…
Thermodynamics A study of the transformation of energy from one form to another, and its practical application. (see Law(s) of Thermodynamics above).
Thermoelectric (power) water use Water used in generating electricity with steam-driven turbine generators. Power plants that burn coal and oil are examples of thermoelectric-power…
Thermoelectric Conversion The conversion of heat into electricity by the use of thermocouples.
Thermograph An instrument that measures and records air temperature.
Thermography (ther-MAH-gruh-fee) In medicine, a procedure in which a heat-sensing infrared camera is used to record the surface heat produced by different parts of the…
Thermohaline Circulation Large-scale density-driven circulation in the ocean, caused by differences in temperature and salinity.
thermohaline circulation (THC) density-driven circulation system in the world's oceans. In the Atlantic, warm water flows northward in the surface ocean, loses heat to the overlying…
thermolabile Not resistant to heat, often in the context of a molecule which is unstable upon heating. Opposite: thermostable.
Thermometer An instrument for measuring air temperature.
thermophile An organism which is adapted to high temperatures, such as in hot springs and geysers, smoker vents on the sea floor, and domestic hot water pipes.
Thermophotovoltaic Cell A device where sunlight concentrated onto a absorber heats it to a high temperature, and the thermal radiation emitted by the absorber is used as the…
Thermopile A large number of thermocouples connected in series.
thermosensitivity Loss of biological activity of a molecule at high temperature.
Thermosiphon The natural, convective movement of air or water due to differences in temperature.
Thermosiphon System This passive solar hot water system consists relies on warm water rising, a phenomenon known as natural convection, to circulate water through the…
Thermosphere The atmospheric shell extending from the top of the mesosphere to outer space. It is a region of more or less steadily increasing temperature with height…
thermostable A molecule which retains its biological activity at some specified higher temperature. Opposite: thermolabile.
Thermostat A device used to control temperatures; used to control the operation of heating and cooling devices by turning the device on or off when a specified…
thermotherapy (THER-moh-THAYR-uh-pee) Treatment of disease using heat.
Theta-e (or Equivalent Potential Temperature) - The temperature a parcel of air would have if a) it was lifted until it became saturated, b) all water vapor was…
Theta-e Ridge An axis of relatively high values of theta-e. Severe weather and excessive rainfall often occur near or just upstream from a theta-e ridge.
THETAE Abbreviation for Theta-e; the temperature a parcel of air would have if a) it was lifted until it became saturated, b) all water vapor was condensed out…
Thiazolidinediones A class of antidiabetes drugs that enhances the activity of insulin.
Thick arch dam An arch dam with a base thickness to structural height ratio of 0.3 or greater (previously defined as 0.5 or greater).
Thickness or width of dam The thickness or width of a dam as measured horizontally between the upstream and downstream faces and normal to the axis or centerline crest of the dam.