[ ee-uh-sin ]
/ ˈi ə sɪn /

noun Chemistry.

Also called bromeosin, tetrabromofluorescein. a red, crystalline, water-insoluble solid, C20H8Br4O5, 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.

Nearby words

  1. eon,
  2. eonian,
  3. eonism,
  4. eop,
  5. eos,
  6. eosine,
  7. eosinopenia,
  8. eosinophil,
  9. eosinophil adenoma,
  10. eosinophil chemotactic factor of anaphylaxis

Also e·o·sine [ee-uh-sin, -seen] /ˈi ə sɪn, -ˌsin/.

Origin of eosin

1865–70; < Greek ēṓs dawn (see eo-) + -in2

Related formse·o·sin·ic, adjectivee·o·sin·like, adjective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for eosin

British Dictionary definitions for eosin


eosine (ˈiːəʊsɪn, -ˌsiːn)

/ (ˈiːəʊsɪn) /


Also called: bromeosin a red crystalline water-insoluble derivative of fluorescein. Its soluble salts are used as dyes. Formula: C 20 H 8 Br 4 O 5
any of several similar dyes
Derived Formseosinic, adjectiveeosin-like, adjective

Word Origin for eosin

C19: from Greek ēōs dawn + -in; referring to the colour it gives to silk

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

Medicine definitions for eosin


[ ēə-sən ]


Any of a class of red acid dyes of the xanthene group used as cytoplasmic stains and as counterstains, especially the sodium and potassium salts of certain of these dyes.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.