/ Dictionary / Index T tautomer: Meaning and Definition of Find definitions for: tau•to•mer Pronunciation: (tô'tu-mur), [key] — n. Chem. a compound that exhibits tautomerism. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tautology tautomerism Related Content Daily Word Quiz: philtrum Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language