Paracosm

Paracosm is a type of imaginary world that a person creates. It's like a pretend world that somebody makes up in their head. It can involve things like make-believe cities, towns, countries, or even entire planets. People who create paracosms often create a whole world with unique characters, stories, and a history. Sometimes they even make up their own language, special rules, and customs. A paracosm is usually something that somebody creates in their head or with drawings and can stay with them for years, growing and changing as they grow and change.