A rump is the backside or rear end of an animal, especially the hindquarters of a four-legged creature like a horse, cow, or dog. If you've ever patted a horse on its rump, you've touched the muscular area above its back legs. Butchers sell rump roast, a cut of beef from this part of the cow.

The word can also describe what's left of something after the important parts are gone. When most members leave an organization, what remains might be called a rump group. After the English Civil War in the 1600s, when many members of Parliament were removed, historians called what remained the Rump Parliament because it was just a small leftover piece of the original body. In this sense, rump suggests something incomplete or diminished, like the stub of a pencil after you've used most of it.

You might also hear rump used informally to describe a person's bottom, though this usage is somewhat old-fashioned and usually meant in a lighthearted way.