Also, tortoise shell.
a horny substance of a mottled brown and yellow coloration, composing the laminae that cover the inner body plates of the carapace of a hawksbill turtle, used for making combs and ornamental articles, inlaying, etc.
any synthetic substance made to look like natural tortoise
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.
mottled or variegated like tortoiseshell, especially with yellow and brown and sometimes other colors.