Nickname

What is a nickname?

A nickname is a familiar and/or humorous name given to a person instead of or as well as the real name.

Etymology of nickname

Nickname literally means 'an additional name', from Old English an eke name (13th century), which was later misinterpreted as a neke name (15th century).

Old English eaca = 'an increase'

The Old Norse cognate is auka-nefi = 'nickname'

Old Norse nicknames

Old Norse nicknames were also called bynames. You can find an explanation of those and long lists here.