[ awr-see-in ]
/ ˈɔr si ɪn /

noun Chemistry.

a red dye, the principal coloring matter of cudbear and orchil, obtained by oxidizing an ammoniacal solution of orcinol.

Origin of orcein

1830–40; arbitrary alteration of orcin; see orcinol
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for orcein


/ (ˈɔːsɪɪn) /


a brown crystalline material formed by the action of ammonia on orcinol and present in orchil: used as a dye, biological stain, and antiseptic. Formula: C 28 H 24 O 7 N 2

Word Origin for orcein

C19: see orcinol
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 orcein


[ ôrsē-ĭn ]


A natural dye derived from orcinol and used in various histologic staining methods as a purple dye complex.

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