/ Dictionary / Index E excimer: Meaning and Definition of Find definitions for: ex•ci•mer Pronunciation: (ek'su-mur), [key] — n. Chem. a molecular complex of two, usually identical, molecules that is stable only when one of them is in an excited state. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. excide excipient Related Content Daily Word Quiz: pedagogy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language