a horny substance of a mottled brown and yellow coloration, composing the laminae that cover the inner body plates of the carapace of certain tortoises or turtles, especially the hawksbill, used for making combs and ornamental articles, inlaying, etc.
any synthetic substance made to look like natural tortoiseshell.
Also, tortoiseshell butterfly. any of several nymphalid butterflies of the genus Nymphalis, as N. californica, having variegated markings of red, yellow, or orange on the wings.
adjective, Also, tortoise-shell
mottled or variegated like tortoiseshell, especially with yellow and brown and sometimes other colors.