A rooster, also known as a cockerel or cock, is a male gallinaceous bird, usually a male chicken (Gallus gallus). Mature male chickens less than one year old are called cockerels. The term "rooster" originates in the United States,and the term is widely used throughout North America, as well as Australia and New Zealand. The older terms "cock" or "cockerel", the latter denoting a young cock, are used in the United Kingdom and Ireland.