This informal meaning refers to the fleshy rear part of the human body.
He slipped and landed on his butt.
The exercise strengthens the legs and butt.
This meaning refers to the short portion left after a cigarette has been smoked.
Do not throw cigarette butts on the ground.
The ashtray was full of butts.
Usually used in the butt of a joke, this meaning refers to the person being mocked.
He became the butt of every office joke.
The character is often the butt of ridicule.