laugh line vs punch line

laugh line and punch line both are nouns.

Word	Noun	Adjective	Verb	Adverb
laugh line	Yes	No	No	No
punch line	Yes	No	No	No

As nouns, laugh line and punch line are synonyms defined as:

Other synonyms of laugh line include gag line, tag line.

laugh line (noun)	punch line (noun)
the point of a joke or humorous story	the point of a joke or humorous story
a wrinkle in the skin at the outer corner of your eyes