S: (n) argon, Ar, atomic number 18 (a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere)
S: (n) helium, He, atomic number 2 (a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas))
S: (n) neon, Ne, atomic number 10 (a colorless odorless gaseous element that give a red glow in a vacuum tube; one of the six inert gasses; occurs in the air in small amounts)
S: (n) radon, Rn, atomic number 86 (a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health)
S: (n) xenon, Xe, atomic number 54 (a colorless odorless inert gaseous element occurring in the earth's atmosphere in trace amounts)
S: (n) chlorine, Cl, atomic number 17 (a common nonmetallic element belonging to the halogens; best known as a heavy yellow irritating toxic gas; used to purify water and as a bleaching agent and disinfectant; occurs naturally only as a salt (as in sea water))
S: (n) fluorine, F, atomic number 9 (a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite)
S: (n) hydrogen, H, atomic number 1 (a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas; the simplest and lightest and most abundant element in the universe)
S: (n) tritium (a radioactive isotope of hydrogen; atoms of tritium have three times the mass of ordinary hydrogen atoms)
S: (n) nitrogen, N, atomic number 7 (a common nonmetallic element that is normally a colorless odorless tasteless inert diatomic gas; constitutes 78 percent of the atmosphere by volume; a constituent of all living tissues)
S: (n) oxygen, O, atomic number 8 (a nonmetallic bivalent element that is normally a colorless odorless tasteless nonflammable diatomic gas; constitutes 21 percent of the atmosphere by volume; the most abundant element in the earth's crust)
S: (n) liquid oxygen, LOX (a bluish translucent magnetic liquid obtained by compressing gaseous oxygen and then cooling it below its boiling point; used as an oxidizer in rocket propellants)
S: (n) butane (occurs in natural gas; used in the manufacture of rubber and fuels)
S: (n) propane (colorless gas found in natural gas and petroleum; used as a fuel)
S: (n) afterdamp (a toxic mixture of gases (including carbon dioxide and carbon monoxide and nitrogen) after an explosion of firedamp in a mine)
S: (n) firedamp (a mixture of gases (mostly methane) that form in coal mines and become explosive when mixed with air)
S: (n) arsine (a poisonous colorless flammable gas used in organic synthesis and to dope transistors and as a poison gas in warfare)
S: (n) air (a mixture of gases (especially oxygen) required for breathing; the stuff that the wind consists of) "air pollution"; "a smell of chemicals in the air"; "open a window and let in some air"; "I need some fresh air"
S: (n) breath (the air that is inhaled and exhaled in respiration) "his sour breath offended her"
S: (n) compressed air (air at a pressure greater than that of the atmosphere) "compressed air is often used to power machines"
S: (n) air cushion (the trapped air that supports a hovercraft a short distance above the water or ground)
S: (n) ethylene, ethene (a flammable colorless gaseous alkene; obtained from petroleum and natural gas and used in manufacturing many other chemicals; sometimes used as an anesthetic)
S: (n) trichloroethylene, trichloroethane, TCE (a heavy colorless highly toxic liquid used as a solvent to clean electronic components and for dry cleaning and as a fumigant; causes cancer and liver and lung damage)
S: (n) producer gas, air gas (a gas made of carbon monoxide and hydrogen and nitrogen; made by passing air over hot coke)
S: (n) chlorofluorocarbon, CFC (a fluorocarbon with chlorine; formerly used as a refrigerant and as a propellant in aerosol cans) "the chlorine in CFCs causes depletion of atmospheric ozone"
S: (n) hydrochlorofluorocarbon, HCFC (a fluorocarbon that is replacing chlorofluorocarbon as a refrigerant and propellant in aerosol cans; considered to be somewhat less destructive to the atmosphere)
S: (n) Freon (any one or more chlorofluorocarbons (or related compounds) that are used as an aerosol propellant, organic solvent, or refrigerant)
S: (n) carbon dioxide, CO2, carbonic acid gas (a heavy odorless colorless gas formed during respiration and by the decomposition of organic substances; absorbed from the air by plants in photosynthesis)
S: (n) chokedamp, blackdamp (the atmosphere in a mine following an explosion; high in carbon dioxide and incapable of supporting life)
S: (n) methane (a colorless odorless gas used as a fuel)
S: (n) marsh gas (methane gas produced when vegetation decomposes in water)
S: (n) ozone (a colorless gas (O3) soluble in alkalis and cold water; a strong oxidizing agent; can be produced by electric discharge in oxygen or by the action of ultraviolet radiation on oxygen in the stratosphere (where it acts as a screen for ultraviolet radiation))
S: (n) phosgene (a colorless poisonous gas that smells like new-mown hay; used in chemical warfare)
S: (n) phosphine (a colorless gas with a strong fishy smell; used as a pesticide)
S: (n) poison gas (a gas that is poisonous to breath or contact; used in chemical warfare)
S: (n) nerve gas, nerve agent (a toxic gas that is inhaled or absorbed through the skin and has harmful effects on the nervous and respiratory system)
S: (n) VX gas (a highly lethal nerve agent used in chemical warfare; a toxic liquid that penetrates the skin or lungs to disrupt the nervous system and stop respiration; in combat VX gas is deployed by detonating a container over the target area and can persist in the environment up to several weeks after release) "VX gas is one of those things we wish we could disinvent"
S: (n) organophosphate nerve agent (any of a series of nerve agents containing organophosphate compounds first synthesized by German chemists in 1936; in World War II the Germans tested them in concentration camps but not on the battlefield; Iraq is alleged to have used them against Iran and against the Kurds)
S: (n) sarin, GB (a highly toxic chemical nerve agent that inhibits the activity of cholinesterase)
S: (n) soman, GD (a nerve agent easily absorbed into the body; a lethal cholinesterase inhibitor that is highly toxic when inhaled)
S: (n) tabun, GA (the first known nerve agent, synthesized by German chemists in 1936; a highly toxic combustible liquid that is soluble in organic solvents and is used as a nerve gas in chemical warfare)
S: (n) propylene, propene (a flammable gas obtained by cracking petroleum; used in organic synthesis)
S: (n) mephitis (a poisonous or foul smelling gas emitted from the earth)
S: (n) sulfur dioxide, sulphur dioxide (a colorless toxic gas (SO2) that occurs in the gases from volcanoes; used in many manufacturing processes and present in industrial emissions; causes acid rain)
S: (n) chlorobenzylidenemalononitrile, CS gas (a tear gas that is stronger than CN gas but wears off faster; can be deployed by grenades or cluster bombs; can cause skin burns and fatal pulmonary edema)
S: (n) Mace, Chemical Mace ((trademark) a liquid that temporarily disables a person; prepared as an aerosol and sprayed in the face, it irritates the eyes and causes dizziness and immobilization)
S: (n) liquid (fluid matter having no fixed shape but a fixed volume)
S: (n) artificial blood (a liquid that can carry large amounts of oxygen and can serve as a temporary substitute for blood)
S: (n) elixir (a sweet flavored liquid (usually containing a small amount of alcohol) used in compounding medicines to be taken by mouth in order to mask an unpleasant taste)
S: (n) water, H2O (binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; widely used as a solvent)
S: (adj) fluid, unstable (subject to change; variable) "a fluid situation fraught with uncertainty"; "everything was unstable following the coup"
S: (adj) fluid, runny (characteristic of a fluid; capable of flowing and easily changing shape)
S: (adj) fluent, fluid, liquid, smooth (smooth and unconstrained in movement) "a long, smooth stride"; "the fluid motion of a cat"; "the liquid grace of a ballerina"
S: (adj) fluid, liquid (in cash or easily convertible to cash) "liquid (or fluid) assets"
S: (adj) fluid, mobile (affording change (especially in social status)) "Britain is not a truly fluid society"; "upwardly mobile"