/ Dictionary / Index G gaseous: Meaning and Definition of Find definitions for: gas•e•ous Pronunciation: (gas'ē-us, gash'us), [key] — adj. existing in the state of a gas; not solid or liquid. pertaining to or having the characteristics of gas. lacking firmness or solidity; uncertain; not definite. gassy (defs. 1, 3). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: gaseous (Thesaurus) gas engine gaseous diffusion Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language