/ Dictionary / Index E ester: Meaning and Definition of Find definitions for: es•ter Pronunciation: (es'tur), [key] — n. Chem. a compound produced by the reaction between an acid and an alcohol with the elimination of a molecule of water, as ethyl acetate, CHO, or dimethyl sulfate, CHSO. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ester (Thesaurus) Estepona esterase Related Content Daily Word Quiz: neologism Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language