I. ˈtȯr-tə-ˌshel, -əsh-ˌshel noun
Date: 1632
1. : the mottled horny substance of the shell of the hawksbill turtle used especially formerly in inlaying and in making various ornamental articles
2. : any of several showy nymphalid butterflies (genera Nymphalis and Aglais )
II. adjective
Date: 1651
1. : made of or resembling tortoiseshell especially in mottled brown and yellow coloring
tortoiseshell glasses
2. : of, relating to, or being a color pattern of the domestic cat consisting of patches of black, orange, and cream