From the Germanic name Lanzo, originally a short form of names that began with the elementland meaning "land". During the Middle Ages it became associated with Old French lance "spear, lance". A famous bearer is American cyclist Lance Armstrong (1971-).
From a surname which was derived from an Old English place name meaning "long hill" (effectively meaning "ridge"). Use of the name may have been inspired in part by the actor Michael Landon (1936-1991).