/ Dictionary / Index T trisodium: Meaning and Definition of Find definitions for: tri•so•di•um Pronunciation: (trī-sō'dē-um), [key] — adj. Chem. pertaining to molecules containing three sodium atoms. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. trisoctahedron trisodium phosphate 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