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.

• (usually in the plural) each of the two large fleshy halves of the posterior part of the body between the base of the back and the top of the legs.
       She fell on her buttocks.