A temporal displacement was a temporal phenomenon in which a certain element from one time period was misplaced into another time period. If not corrected, a temporal displacement could have devastating effects on the timeline.
In 2372, Benjamin Sisko was held in a temporal displacement after a warp core accident caused by a subspace inversion of the Bajoran wormhole. When Jake Sisko sent his father back in time, he corrected the temporal displacement. (DS9: "The Visitor")