con·chi·o·lin noun alsocon·chy·o·lin\käŋˈkīələ̇n also kȯŋ-\ (-s) Etymology:conchiolin from conch- + -i- + -ol + -in; conchyolin alteration of conchiolin : a scleroprotein forming the organic basis of mollusk shells (as mother-of-pearl) — see nacre 2