Teleportation is defined by Wikipedia as the instantaneous transportation of matter from one point in space to another. Various continua feature teleportation as either a technological, supernatural, or magical ability. For example, the transporters in the Star Trek universe employ a form of technological teleportation to "beam" people and objects from one location to another. Within the Harry Potter continuum, some characters have the ability to transport themselves via magic; this is known in-universe as Apparation.
Unless the canon allows for such occurrences, a character having the power to do this constitutes a charge, as in the case of Leif Melyamos of "soulless shell" (MSTed by Lycaenion: part 1, part 2).
Unintentional teleportation occurs quite often in fics in which the author isn't paying attention to the characters' location. For example, "Like it or not" (Part 1) (NSFW), in which Murdoc and 2D of Gorillaz were apparently capable of teleporting out of a wrecked car, as the author forgot to mention them escaping and they showed up unharmed later on.