What are "punch-lines"?

Question

In a song?!

Answer 1

a punch-line is a part of a joke. The part which comes after the set up. Where the humor actually hits, and makes it funny. For example:

Joe: Knock-knock.

Sally: Who's There?

Joe: Boo.

Sally: Boo who?

(Everything up to this point has been the "Set-Up" of the joke)

Joe: Don't cry. It's only a joke! <-- Punch Line

The joke is that when "Boo Who" is read aloud, it sounds like "boo-hoo" the accepted mimicry of a person crying. So when Sally inadvertently makes the "Crying sound" meaning only to ask who "Boo" is. Joe comes with the punchline of  "Don't cry"

Tadaaa! Funny

(Yeah Right lol)

Answer 2

"Punchline" is a Beach Boy song... not sure if that is what you meant.

Answer 3

usually a punch line is the final part of a joke, the part everyone waits for to laugh

kinda like "whats the catch" of the joke/song

Answer 4

OH, okay, I get it. The punch-lines they are referring to are like battles: Each person, consisting of at least two people, are insulting each other. So, they're insults.