From Longman Dictionary of Contemporary Englishpunchlinepunch‧line, punch line /ˈpʌntʃlaɪn/ noun [countable usually singular] APJOKEthe last few words of a joke or story, that make it funny or surprising
Examples from the Corpus
punchline• I got it all back to front, and couldn't think of a punchline.• And of course, there isn't a punchline but the ending goes something like this.• It's like an extended Beadle's About sketch without a punchline.• Professor Ito blinks, shakes his head, then translates my punchline.• The signalman guffawed at his own punchline then disappeared from view, closing the window after him.• At the punchline, Maria laughed much harder than the joke deserved. 