/ Dictionary / Index I ideal gas: Meaning and Definition of Find definitions for: ide'al gas' Pronunciation: [key] — Physics. Physics. a gas composed of molecules on which no forces act except upon collision with one another and with the walls of the container in which the gas is enclosed; a gas that obeys the ideal gas law. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ideal ideal gas law Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language