continuous amorphous matter that tends to flow and to conform to the outline of its container: a liquid or a gas

existing as or having characteristics of a gas

turn into gas

the envelope of gases surrounding any celestial body

any of the chemically inert gaseous elements of the helium group in the periodic table

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)

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

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