The term jumping the shark alludes to a specific scene in a 1977 episode of the TV series Happy Days when the popular character Arthur "Fonzie" Fonzarelli literally jumps over a shark while water skiing. The scene was so preposterous that many believed it to be an ill-conceived attempt at reviving the declining ratings of the flagging show. Since then, the phrase has become a colloquialism used by U.S. TV critics and fans to denote the point at which the characters or plot of a TV series veer into a ridiculous, out-of-the-ordinary storyline. Such a show is typically deemed to have passed its peak. Once a show has "jumped the shark" fans sense a noticeable decline in quality or feel the show has undergone too many changes to retain its original charm.

Jump-the-shark moments may be scenes like the one described above that finally convince viewers that the show has fundamentally and permanently strayed from its original premise. In those cases they are viewed as a desperate and futile attempt to keep a series fresh in the face of declining ratings. In other cases the departure or replacement of a main cast member or character or a significant change in setting changes a critical dynamic of the show. These changes are often attempts to attract their fans' waning attention with over-the-top statements or increasingly overt appeals to sex or violence.

The term has also evolved to describe other areas of pop culture including movie series, music or acting celebrities, or authors for whom a drastic change was seen as the beginning of the end or marking the moment the subject is "past its peak."