What is a concept or thing you became aware of that you can explain fluently but that you do not (yet) possess the word or phrase to coin it with?

Kind like that thing where ones native language doesnt have a specific pithy single word or phrasal expression to store its meaning

For extra fun (see my example in the replies) give

the fluent explanation

SPOILER (even if you dont have it, just leave it blank if you dont so people dont know whether there's an answer beforehand