Definition of "punch line"

punch line

/ˈpʌntʃˌlaɪn/

noun
plural punch lines
1. The final part of a joke; the word, sentence, or exchange of sentences that is intended to be funny and provokes laughter from the listeners.
  Quotations
  While explaining a punchline might initially kill the joke, Roberts claims it can shed light on the use of humour in language and help students remember the gag for future use.
  2014 August 20, Matthew Jenkin, “Why language learners don't have to miss the punchline”, in The Guardian‎
2. (by extension) The butt of a joke; laughing stock.
  Quotations
  The women are a phenomenon; the men are a punchline.
  2019 July 8, Tom Dart, “The US men's team are now a punchline. Which is a little unfair”, in The Guardian‎
  (It didn’t help when Microsoft relaunched its Bing search engine with OpenAI’s technology inside, instantly ending Bing’s decade-long run as a punchline.)
  2023 March 31, Kevin Roose, “Google C.E.O. Sundar Pichai on the A.I. Moment: ‘You Will See Us Be Bold’”, in The New York Times‎
3. (by extension) A final, concluding statement that an explanation has been leading up to; a conclusion.
  Quotations
  The final, the Munich-based liberal newspaper writes, was a “fitting punchline” to a great tournament.
  2014 July 14, Philip Oltermann, “World Cup final press reaction: Germany’s win a ‘fitting punchline’”, in The Guardian‎