A practical joke or prank is a trick played on people or people, generally causing the victim to experience embarrassment, perplexity, confusion, or discomfort. The perpetrator of a practical joke is called a "practical joker" or "prankster". Other terms for practical jokes include gag, rib, jape, or shenanigan. Some countries in western nations make it tradition to carry out pranks on April Fools' Day and Mischief Night.

A joke is a display of humour in which words are used within a specific and well-defined narrative structure to make people laugh and is usually not meant to be interpreted literally. It usually takes the form of a story, often with dialogue, and ends in a punch line, whereby the humorous element of the story is revealed; this can be done using a pun or other type of word play, irony or sarcasm, logical incompatibility, hyperbole, or other means. Linguist Robert Hetzron offers the definition:A joke is a short humorous piece of oral literature in which the funniness culminates in the final sentence, called the punchline… In fact, the main condition is that the tension should reach its highest level at the very end. No continuation relieving the tension should be added. As for its being "oral," it is true that jokes may appear printed, but when further transferred, there is no obligation to reproduce the text verbatim, as in the case of poetry.