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 not meant to be taken seriously. It takes the form of a story, usually with dialogue, and ends in a punch line. It is in the punch line that the audience becomes aware that the story contains a second, conflicting meaning. This can be done using a pun or other word play such as irony or sarcasm, a logical incompatibility, nonsense, 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.