What is a time loop?

Normally, a loop is a geometrical figure which, when traversed, results in getting back to the same point from where one started. A time loop, also known as temporal loop, is a common plot device in science fiction in which time runs normally for a set period, usually a day or maybe a few hours but then skips back to the starting point. When the time loop "resets", the memories of most characters are also reset to the original's space.

Geometrical figure, Temporal loop, Science fiction, Starting point, Memories of most characters, Original space