What is the meaning of Nickname?

A familiar, invented name for a person or thing used instead of the actual name of the person or thing, often based on some noteworthy characteristic.

A familiar, shortened or diminutive name for a person or thing.

To give a nickname to (a person or thing).

Arika Okrent (2019 July 5) “12 Old Words That Survived by Getting Fossilized in Idioms”, in Mental Floss, Pocket, retrieved 2021-10-08

Source: wiktionary.org