A wipe is a Scene Transition in which one scene overlaps another, often appearing to physically "push" the frame over. One of the old classics. Can be horizontal, vertical, diagonal, radial, or otherwise. In the digital era, wipes are effortless, and the boundary between the scenes need no longer be straight.
A radial wipe to black produces the Iris Out effect. Much like the way beginning digital graphic artists abuse Photoshop filters, overuse of wipes is a trademark of an inexperienced editor in love with his equipment: see an episode of The Simpsons for an example ("And star wipe to Flanders...")
An MTV Wayne's World special featured a performance of a song by Wayne and Garth that included a "switcher solo" featuring a multitude of wipes as a joke (albeit one that only people with a certain amount of knowledge of video production will get).
Some series have unique scene transitions that represent a point of style. See Idiosyncratic Wipes.