"moving quickly," related to swifan
"move in a course, sweep" (see swivel
). The bird (several species of the family Cypselidæ,
resembling swallows), noted for its "swift" flight, was so called from at least 1668. Regarded as a bird of ill-omen, if not downright demonic, probably for its shrill cry. The name earlier had been given to several small fast lizards (1530).