/ Dictionary / Index E eosin: Meaning and Definition of Find definitions for: e•o•sin Pronunciation: (ē'u-sin), [key] — n. Chem. Also calleda red, crystalline, water-insoluble solid, CHBrO, derived from fluorescein by bromination: used chiefly as an acid dye for dyeing silk a rose red color and as a histological stain. any of a variety of eosinlike dyes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: eosin (Thesaurus) Eos eosinophil Related Content Daily Word Quiz: cygnet Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language