Boy

A boy is a male human child, as contrasted to a female child, which is a girl. The term "boy" is used to indicate biological sex distinctions, cultural gender role distinctions, or both. An adult male human is a man.
The boundary is not clear cut. In English, a youth or a teenager may be either male or female. No term currectly exists for an intermediate stage between a boy and a man.
Many occasions occur when an adult male could be referred to as a boy. A man or woman will refer to a boyfriend in one or two words regardless of age. A man's group of male friends are often "the boys". A young man who has not assumed (or has been denied) the traditional roles of a man might also be called a boy.
In the U.S. the word is sometimes used disparagingly for a black man or (historically) for a male slave. It was also widely applied to black men in South Africa in the Apartheid era, and (mainly historically) to black men in many other contexts. In the UK, football managers quite often refer to footballers as "The boy so-and-so" and this usage is by no means restricted to the youngest players, though it is rarely applied to the most senior.