/ Dictionary / Index F fluorescein: Meaning and Definition of Find definitions for: fluo•res•ce•in Pronunciation: (floo--res'ē-in, flô-, flō-), [key] — n. Chem. an orange-red, crystalline, water-insoluble solid, CHO, that in alkaline solutions produces an orange color and an intense green fluorescence: used to trace subterranean waters and in dyes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fluorescein (Thesaurus) fluoresce fluorescence Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language