In the U.S.A., Canada and Australia, adult male chickens are known as roosters; in the UK they are known as cocks.[citation needed] Males under a year old are cockerels.[5] Castrated roosters are called capons (though both surgical and chemical castration are now illegal in some parts of the world). Females over a year old are known as hens, and younger females are pullets.[6] In Australia and New Zealand (also sometimes in Britain), there is a useful generic term chook (rhymes with "book") to describe all ages and both genders.[7] Babies are called chicks, and the meat is called chicken.

"Chicken" was originally the word only for chicks, and the species as a whole was then called domestic fowl, or just fowl. This use of "chicken" survives in the phrase "Hen and Chickens," sometimes used as a UK pub or theatre name, and to name groups of one large and many small rocks or islands in the sea (see for example Hen and Chicken Islands).