Glacial tillAn unsorted, unstratified mixture of fine and coarse rock debris deposited by a glacier.
GlaciationThe transformation of cloud particles from water drops to ice crystals. Thus, a cumulonimbus cloud is said to have a "glaciated" upper portion.
GlacierBodies of land ice that consist of recrystallized snow accumulated on the surface of the ground, and that move slowly downslope.
Glacier (ice sheet)A large thick mass of ice formed on land by the compacting and recrystallization of old snow and move under the influence of gravity.
Glacier Dammed LakeThe lake formed when a glacier flows across the mouth of an adjoining valley and forms an ice dam.
Glacier WindA shallow downslope wind above the surface of a glacier, caused by the temperature difference between the air in contact with the glacier and the free air…
glandAn organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk.
GlareThe excessive brightness from a direct light source that makes it difficult to see what one wishes to see.
Glauber's SaltA salt, sodium sulfate decahydrate, that melts at 90 degrees Fahrenheit; a component of eutectic salts that can be used for storing heat.
glaucousA surface with a waxy, white coating. In most cases, this waxy covering can be rubbed off.
GlazeIce formed by freezing precipitation covering the ground or exposed objects.
GlazingThe material, usually glass, that fills spaces between sash members (rails, stiles and muntins), commonly referred to as panes or lights.
GLF(Open Lakes Forecast) - A National Weather Service marine forecast product for the U.S.
GliaThe nonneuronal or supporting tissue (neuroglia) of the brain and spinal cord.
Glial cells(glee'-ul sells) branched cells that make up the supporting structure of the nervous (brain & spinal cord) tissue.
GlintA momentary flash of light resulting from a spatially localized reflection of sunlight. See also Glare
Global Forecast System(GFS)- One of the operational forecast models run at NCEP. The GFS is run four times daily, with forecast output out to 384 hours.
Global Observing SystemGlobal Observing System (GOS) Global network of observational stations which is the coordinated system of methods, techniques and facilities for making…
Global Positioning System (GPS)(GPS)A navigation system which uses a constellation of artificial earth satellites to make precise determinations of the latitude and longitude of locations on…
Global positioning systems (GPS)Space-based radio positioning systems that provide 24-hour, three-dimensional position, velocity, and time information to suitably equipped users anywhere…
Global Telecommunication SystemGlobal Telecommunication System (GTS) The coordinated global system of telecommunication facilities and arrangements for the rapid collection, exchange…
Global Temperature ChangeThe net result of four primary factors including the greenhouse effect, changes in incoming solar radiation, altered patterns of ocean circulations, and…
Global WarmingA popular term used to describe the increase in average global temperatures due to the greenhouse effect.
Global Warming Potential (GWP)Global Warming Potential (GWP) is defined as the cumulative radiative forcing effects of a gas over a specified time horizon resulting from the emission…
Globex (GW)(GW)The electronic trading platform for the Chicago Mercantile Exchange (CME). Since Sept.
Globular ClustersA collection of hundreds of thousands of old stars held together by gravity.
globulinsCommon class of proteins in blood, eggs and milk, and seeds. Characterized by their slight solubility in water but are freely soluble in dilute salt…
GloryAn optical effect characterized by concentric rings of color (red outermost and violet innermost) surrounding the shadow of an observer's head when the…
GLS(Great Lakes Storm Summary) A National Weather Service forecast product providing updated information whenever a storm warning is in effect on any of the…
GlucagonA hormone produced by the pancreas that increases the level of glucose (sugar) in the blood.
glucanThe polymer of glucose with a repeating unit of C6H10O5. Cellulose is a form of glucan. Can be hydrolyzed to glucose. (Source: Voet, D.; Voet, J. G.
glucocorticoidA compound that belongs to the family of compounds called corticosteroids (steroids).
glucoseA type of sugar; the chief source of energy for living organisms.
glucose invertaseAn enzyme that catalyses the hydrolysis of sucrose into its component monosaccharides, glucose and fructose.
glucose isomeraseAn enzyme that catalyses the interconversion of the two sugars, glucose and fructose.
glucosinolatesA class of molecules produced in the seeds and green tissue of a range of plants, in particular brassicas.
GluonThe carrier particle of the strong interactions. It holds quarks together and the atom's nucleus together.
glutenA mixture of two seed storage protein classes, gliadin and glutenin, found in the endosperm of cereal (particularly wheat) grain.
glycerin(C3H8O3) A liquid by-product of biodiesel production. Glycerin is used in the manufacture of dynamite, cosmetics, liquid soaps, inks, and lubricants.
glycoalkaloidsA group of modified alkaloids, including solanine and tomatine, having a range of toxic effects in humans and other species.
glycoformOne of several structures possible for a given glycoprotein, determined by the type and position of attachment of the component oligosaccharide (s).
glycolysisA process in which glucose (sugar) is partially broken down by cells in enzyme reactions that do not need oxygen.
glycoproteinA protein that has sugar molecules attached to it.
glycoprotein remodellingThe use of restriction endoglycosidases to enzymatically remove oligosaccharide branches from glycoprotein molecules.
glycosylationThe covalent addition of sugar or sugar-related molecules to other classes of molecule, including proteins or nucleic acids.
glyphosateAn active ingredient in some herbicides, killing plants by inhibiting the activity of plant enolpyruvyl-shikimate 3-phosphate synthase.
glyphosate oxidaseAn enzyme which catalyses the break-down of glyphosate, discovered in a strain of Pseudomonas bacteria which were found to produce unusually large amounts…
glyphosate oxidoreductaseAn enzyme from the micro-organism Ochrobactrum anthropi, which catalyses the break-down of glyphosate.
GM foodAbbreviation for genetically modified food. Food that contains above a certain legal minimum content of raw material obtained from genetically modified…
GMDSS(Global Maritime Distress and Safety System)- The Global Maritime Distress and Safety System (GMDSS) is intended to provide more effective and efficient…
GMNOn a buoy report, the minute of the hour that the GSP occurred, reported at the last hourly 10-minute segment.
GOESGeostationary Operational Environmental Satellite- Satellites orbiting at 22,370 miles above the Earth's surface with the same rotational velocity as the…
GOES Data Collection System (DCS)(DCS)A data collection system under NESDIS which is comprised of the DCPs, and the NESDIS Command and Data Acquisition (CDA) System components.
golden riceA biotechnology-derived rice, which contains large amounts of beta carotene (a precursor of vitamin A) in its seeds.
Golgi apparatusAn assembly of vesicles and folded membranes within the cytoplasm of plant and animal cells that stores and transports secretory products (such as enzymes…
gonadThe part of the reproductive system that produces and releases eggs (ovary) or sperm (testicle/testis).
Gonadal ridgeAnatomic site in the early fetus where primordial germ cells (PGCs) are formed.
Gonadal ridgesEmbryonic structures arising in humans at about five weeks, eventually developing into gonads (either testes or ovaries).
GonadsThe embryonic sex gland before it becomes a definitive testis or ovary.
Good Laboratory Practicean approved method to perform a basic operation, activity, or service in a laboratory which influences or enhances the quality of its output.
good manufacturing practice(Abbreviation: GMP). Codes of practice designed to reduce to a minimum the chance of procedural or instrument/manufacturing plant problems which could…
GoosecoidGene that encodes a transcription factor that is important for determining craniofacial orientation and features in the vertebrate embryo.
GovernorA device used to regulate motor speed, or, in a wind energy conversion system, to control the rotational speed of the rotor.
GPSAn acronym for Global Positioning System. A network of satellites which provide extremely accurate position and time information.
gr/SCFGrains of pollutant per standard cubic foot of gas. A measure of dust particles in a gas stream.
GrabenDown-dropped block of rock bounded on both sides by faults. See fault-block.
Graben (fault-bounded basins)An elongated crustal block that is relatively depressed (down dropped) between two parallel normal faults or horsts. See also Half-graben
GRADGradient- A rate of change with respect to distance of a variable quantity, as temperature or pressure, in the direction of maximum change.
GradationProportion of material of each grain-size present in a given soil. The proportions by mass of a soil or fragmented rock distributed in specified…
Grade (pitch)The elevation of a surface or a surface slope. The elevation of the invert of the bottom of a pipeline, canal, culvert, or conduit.
Grade stakeA stake indicating the amount of cut or fill required to bring the ground to a specified level.
Graded streamStreams that receive and carry away equal amounts of sediment.
GraderA machine with a centrally located blade that can be angled to cast to either side, with independent hoist control on each side.
GradientGeneral slope or rate of change in vertical elevation per unit of horizontal distance of water surface of a flowing stream.
Gradient High WindsThese high winds usually cover a large area and are due to synoptic-scale, extra-tropical low pressure systems.
Gradient windGradient wind The same as geostrophic wind, but blowing parallel to curved isobars or contours.
Gradual CommencementIn solar-terrestrial terms, the commencement of a geomagnetic storm that has no well-defined onset
graftHealthy skin, bone, or other tissue taken from one part of the body and used to replace diseased or injured tissue removed from another part of the body.
graft chimeraA plant which is a mosaic of two sorts of tissue differing in genetic constitution and assumed to have arisen as the result of a nuclear fusion following…
graft hybridAn individual formed from graft (2) and stock showing the characteristics of both progenitors. See: graft chimera.
graft inoculation testA test based on the use of a suspected viral carrier which is grafted to an indicator plant.
graft unionThe point at which a scion from one plant is joined to a rootstock from another plant.
Graft Versus Host Disease (GVHD)A side effect of a bone marrow or stem cell transplant that occurs when new bone marrow or stem cells (the graft) reject or attack the patient's body (the…
graft-versus-host disease(... dih-ZEEZ) A disease caused when cells from a donated stem cell graft attack the normal tissue of the transplant patient.