something used instead of a person's realname that either makes it shorter, is a joke, or is a word that describes their personality
Jonathan's friends gave him many nicknames including Tubby due to this large size.
A nickname is a term of familiarity between a person or a thing/another person.
Friend: "I need a new nickname Snugglethug!"
Snugglethug: "How about Two-Dipp?!"
A name that someone gives you because they don't like your real name
Huh... so your name is Robert... boring name, your nickname is now Bob! Hi Bob!
The self you wish you could be based on what a name sounds like or means.
Betty nicknamed herself Charlotte because she wanted to appear more mature.