|   Secret, by Eugen von Blaas  | |
| Alternative names | 
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|---|---|
| Type of joke | Esoteric | 
An in-joke, also known as an inside joke or a private joke, is a joke with humour that is understandable only to members of an in-group; that is, people who are in a particular social group, occupation, or other community of shared interest. It is, therefore, an esoteric joke, only humorous to those who are aware of the circumstances behind it. [1]
Typically, inside jokes use a reference in the punchline to imply that which is associated with the reference. Often, this reference refers to the punchline of another joke which was already heard by the in-group.
In-jokes may exist within a small social clique, such as a group of friends, or extend to an entire profession or other relatively large group. When the in-group only includes people which heard the previous portion of a comedic set, the type of inside joke is known as a callback.
An example is:
Individuals not familiar with the mathematical result Zorn's lemma are unlikely to understand the joke. The joke is a pun on the name of this result.
Ethnic or religious groups may also have in-jokes. [3]
In-jokes are cryptic allusions to shared common ground that act as selective triggers; only those who share that common ground are able to respond appropriately. [4] An in-joke may be used to build community, sometimes at the expense of outsiders. Part of the power of an in-joke is that its audience knows that many do not understand it. [5]
An in-joke can also be used as a subtext, where people in the know may find humor in something not explicitly spoken. They may even apologize for doing so to a rookie, directly or indirectly stating that what they were laughing at was an in-joke. [6]
 Media related to  In-jokes  at Wikimedia Commons
  Media related to  In-jokes  at Wikimedia Commons