1. Something said or done to evoke laughter or amusement, especially an amusing story with a punch line.
2. A mischievous trick; a prank.
3. An amusing or ludicrous incident or situation.
4. Informal
   1. Something not to be taken seriously; a triviality: The accident was no joke.
   2. An object of amusement or laughter; a laughingstock: His loud tie was the joke of the office.

1. To tell or play jokes; jest.
2. To speak in fun; be facetious.

Synonyms: These nouns refer to something that is said or done in order to evoke laughter or amusement. Joke especially denotes an amusing story with a punch line at the end: told jokes at the party.
Jest suggests frolicsome humor: amusing jests that defused the tense situation.
A witticism is a witty, usually cleverly phrased remark: a speech full of witticisms.
A quip is a clever, pointed, often sarcastic remark: responded to the tough questions with quips.
Sally denotes a sudden quick witticism: ended the debate with a brilliant sally.
Crack and wisecrack refer less formally to flippant or sarcastic retorts: made a crack about my driving ability; punished for making wisecracks in class.
Gag is principally applicable to a broadly comic remark or to comic by-play in a theatrical routine: one of the most memorable gags in the history of vaudeville.