• Webster's Revised Unabridged Dictionary
    • Erythrin (Chem) A colorless crystalline substance, C20H22O10, extracted from certain lichens, as the various species of Rocella. It is a derivative of orsellinic acid. So called because of certain red compounds derived from it. Called also erythric acid.
    • Erythrin (Min) See Erythrite, 2.
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Century Dictionary and Cyclopedia
    • n erythrin An organic principle (C20H22O10) obtained from Roccella tinctoria, Lecanora tartarea, and other lichens, which furnish the blue dyestuff called litmus. It is a crystalline compound formed by the union of ether, orsellinic acid, and erythrite. Also called erythric acid, erythrinic acid.
    • n erythrin Same as erythrite, 1.
    • n erythrin A coal-tar color of the xanthene type, prepared by the methylation of eosin. It dyes silk a bluish red with a red fluorescence. Also called primrose.
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Webster's Revised Unabridged Dictionary
Gr. 'eryqro`s red