Definitions

1. noun

The back part of the human body below the waist, especially the part of the hip joint.

“She fell and bruised her buttock on the rocky surface.”

2. noun

A rounded protuberance on an invertebrate animal, such as a snail, where it stores its internal organs.

“The snail’s large buttock helped protect its internal organs from predators.”

3. noun

A projecting mass of rock or soil on a hillside.

“The trekkers had to climb over a steep buttock to reach the summit.”