/ Dictionary / Index A amphithalamus: Meaning and Definition of Find definitions for: am•phi•thal•a•mus Pronunciation: (am"fu-thal'u-mus), [key] — pl. -mi (in an ancient Greek house) a room adjoining the thalamus. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. amphistylar amphitheater Related Content Daily Word Quiz: tactful Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language