“Fun” is a very hard term to define. The lack of a well-agreed to definition is one reason why finding scientific literature studying “fun” is next to impossible.
Do disambiguate more general usages of the word “fun” from a more strict definition of “fun” used in The Power of Fun, Catherine Prince coined the Nonce ”true fun” which is, in short, “playful connected Flow”. True fun is what it’s called when you’re experiencing these three things simultaneously:
- Playfulness - doing a thing for the sake of doing it
- Connection - that which makes you a part of something outside yourself, typically other humans, but also could be God
- Flow - defined in that note, but basically the feeling of being fully engaged and present in what you’re doing
It’s possible to experience only one or two of these things, but to meet the strict ”true fun” definition means achieve all 3 at once.