Words aren’t created by definitions.

Definitions are summaries of the usage of words.

Usage comes first, not definition. Dictionaries, glossaries, etc. are a commentary on usage, attempting to explain to new users of a word what the other people already using that word mean by it.

If someone starts calling some teddy-bears “squee-bears”, they don’t have to have a written-out definition in mind before they do this. Maybe later, if the term “squee-bear” catches on, someone will write down a definition for it, as a summary of how they’ve observed the term being used.