/ Dictionary / Index T trisome: Meaning and Definition of Find definitions for: tri•some Pronunciation: (trī'sōm), [key] — n. Genetics. a trisomic individual. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. trisodium phosphate trisomic Related Content Daily Word Quiz: panacea Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language