• Webster's Revised Unabridged Dictionary
    • n Orcein (Chem) A reddish brown amorphous dyestuff, C7H7NO3, obtained from orcin, and forming the essential coloring matter of cudbear and archil. It is closely related to litmus.
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Century Dictionary and Cyclopedia
    • n orcein A nitrogenous compound (C7H7NO3) formed from orcine and ammonia. It is a deep-red powder of strong tinctorial power, and when dissolved in ammonia is the basis of the archil of commerce. See orcine.
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