A graphic of a temporal causality loop.
A temporal causality loop (or simply temporal loop) is a special condition of time, in which time runs for a certain period, then resets itself to a point back in time, after which the events play out over again. However, afterimages of previous loops can be found to have effect on the dekyon field. This causes humanoid lifeforms to experience déjà vu.
In 2152, NX-01 Enterprise encountered a small 31st century time ship. When the ship's power was restored, a temporal casuality loop was created in Enterprise's launch bay due to the temporal radiation emitted from the pod. (ENT: "Future Tense")
A causality loop can be caused by an antimatter explosion in close proximity to a temporal anomaly. The USS Bozeman and the USS Enterprise-D were caught in a causality loop after they collided near a temporal anomaly in the Typhon Expanse. (TNG: "Cause and Effect")
Upon his arrival aboard USS Voyager, Q, Junior trapped Captain Janeway's crew in a temporal loop, forcing them keep experiencing the same thirty seconds over and over. He described it as "almost as monotonous as drone boy's essay" on James T. Kirk, which in itself was compared to a Vulcan funeral dirge. (VOY: "Q2")
Apocrypha
In the event of an unsuccessful player outcome in the board game Star Trek: The Next Generation - A Klingon Challenge, it is revealed that the ship entered a time loop prior to the adventure, thus giving players another chance to retake the ship.