noun

1. the hard, mottled, yellow-and-brown shell of some turtles and tortoises, used in inlaying and, esp. formerly, in making combs, frames for eyeglasses, etc.
2. a synthetic substance made in imitation of this
3. a mottled, yellow-and-brown color pattern
4. any of several common, black and yellow-brown butterflies (genus Nymphalis) with markings resembling those of tortoise shell
5. a cat with a mottled coat of black, brown, red or yellow, white, etc.