or flu·o·res·ce·ine

[ floo-res-ee-in, flaw-, floh- ]

  1. an orange-red, crystalline, water-insoluble solid, C20H12O5, that in alkaline solutions produces an orange color and an intense green fluorescence: used to trace subterranean waters and in dyes.

Origin of fluorescein

First recorded in 1875–80; fluoresce + -in2

Words Nearby fluorescein

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How to use fluorescein in a sentence

British Dictionary definitions for fluorescein



/ (ˌflʊəˈrɛsɪɪn) /

  1. an orange-red crystalline compound that in aqueous solution exhibits a greenish-yellow fluorescence in reflected light and is reddish-orange in transmitted light: used as a marker in sea water and as an indicator. Formula: C 20 H 12 O 5

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for fluorescein


[ flu-rĕsē-ĭn, flô- ]

  1. An orange-red crystalline compound that exhibits intense fluorescence in alkaline solution. It is used in medicine for diagnostic purposes, in oceanography as a tracer, and as a textile dye. Chemical formula: C20H12O5.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.