A rooster is the US-centric term for a male chicken (the female is a hen), reputedly so named because it roosts over clutches of eggs. In fact, "roosting" is the action of perching aloft and is done by both sexes. The original name, still in use in most of the English speaking world, is "cock" (or "cockerel" if under one year old), which may have been dropped by Americans for prudish reasons.
The Rooster is one of the 12-year cycle of animals which appear in the Chinese zodiac related to the Chinese calendar. It is thought that each animal is associated with certain personality traits. See also: Rooster (Zodiac).
A rooster from the Barred Plymouth Rock breed, caught in the act of crowing.