First term looked up failed

I downloaded this after seeing many people use tbt in posts. I had already looked it up on the web. Then thought there must be an app for that. Well there is but something as basic as tbt is not listed. On the internet about 10 sites came up answering it, so its not uncommon. And if my friends who are NOT teens or twenties or... Well you get the idea, are using it - it has to be relatively mainstream.

Cleopatra peanut about Slang Dictionary