屁股的半邊肉,屁股,船尾背摔
Buttock \But"tock\, n. [From {Butt} an end.] 1. The part at the back of the hip, which, in man, forms one of the rounded protuberances on which he sits; the rump. 2. (Naut.) The convexity of a ship behind, under the stern. --Mar. Dict.
buttock n : either of the two large fleshy masses of muscular tissue that form the human rump [syn: {cheek}]