Nickname

A nickname (also spelled "nick name") is a descriptive name given in place of or in addition to the official name of a person, place or thing. It can also be the familiar or truncated form of the proper name, which may sometimes be used simply for convenience (ex. "Bob", "Bobby", "Rob", "Robbie", "Hob", and "Bert" for the name Robert) The term hypocoristic is used to refer to a nickname of affection between those in love or with a close emotional bond, compared with a term of endearment. The term diminutive name refers to nicknames that convey smallness, hence something regarded with affection or familiarity (e.g., referring to children,) or contempt. Shorter Oxford English Dictionary, The distinction between the two is often blurred.