orcein Chem.
(ˈɔːsiːɪn)
[Altered from orcin.]
A red colouring-matter (C7H7NO3) obtained from orcin by the action of ammonia and oxygen, and existing in the dye called orchil.
| 1838 T. Thomson Chem. Org. Bodies 404 To the substance into which orcin is converted by the joint action of oxygen, ammonia, and water, Robiquet has given the name of orcein. 1876 Harley Mat. Med. (ed. 6) 363 The blue colouring matter called orcein, which is the essential constituent of these dyes. |