/ Dictionary / Index E expansion chamber: Meaning and Definition of Find definitions for: expan'sion cham"ber Pronunciation: [key] — Physics. Physics. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. expansion card expansionism Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language