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Webster 1913 Edition

(fī′brō̍-ĭn or fĭb′rō̍-ĭn)

Noun.

[L.

fibra

a fiber.]

(Chem.)

A variety of gelatin; the chief ingredient of raw silk, extracted as a white amorphous mass.

fibroin ‎(plural fibroins)

(biochemistry) A tough elastic protein that is the main component of silk and of spider's webs

protein