A temporal paradox in which a time traveller's actions in the past turn out to be the cause of the events that sent them back, a recurring problem for Starfleet crews.
The predestination paradox is named in the Deep Space Nine episode Trials and Tribble-ations, where the Temporal Investigations agents Dulmur and Lucsly groan at the thought that Sisko might have become his own ancestor or otherwise caused the history he visited.
The franchise has several clear examples. In Time's Arrow the discovery of Data's head in a cavern sets off the journey to 1893 during which he loses it. In Past Tense Sisko takes the place of Gabriel Bell and becomes the man in the historical record. In Star Trek IV Scott gives away the formula for transparent aluminium, remarking that its inventor may be the man he gives it to.
Voyager's Captain Braxton of the 29th century offers the same idea in other words in Future's End, describing a chain of events in which A leads to B, B to C and C back to A.