the chimney swift's genus name, "chaetura", is a combination of two ancient greek words: "chaite", which means "bristle" or "spine", and "oura" which means "tail". this is an apt description of the bird's tail, as the shafts of all ten tail feathers (rectrices) end in sharp, protruding points. the specific name "pelagica" is derived from the greek word "pelagikos", which means "of the sea". this is thought to be a reference to its nomadic lifestyle rather than to any reference to the sea, a theory strengthened by the later assignment of the specific name "pelasgia" (after the nomadic pelasgi tribe of ancient greece) to the same species by other ornithologists. its common name refers to its preferred nesting site and its speedy flight.