Punchline

joke, usually the word, sentence or exchange of sentences which is supposedly "funny" and provokes laughter from the listeners.

For instance, in the following well-known joke:

A man walks into a bar with a duck under his arm.

The bartender asks: "hey, where did you find the pig?"

"It's not a pig, it's a duck," the man answers.

To which the barman replies: "I was talking to the duck".

"I was talking to the duck" is the punch line - if people laugh at the joke, it's when they hear that part.

Punch lines generally derive their humor from being unexpected. "Punch line" is probably an Americanism, but the "punch" could be related to Punch magazine or the act of a punch. In previous centuries, a joke was sometimes a "bite" or a "hit."

Punchline is also the name of a 1988 film. See Punchline (film).