/ Dictionary / Index E equation of state: Meaning and Definition of Find definitions for: equa'tion of state' Pronunciation: [key] — Physics. Physics. an equation relating the temperature, pressure, and volume of a given thermodynamic system. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. equation of motion equation of time Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language