What's the Difference Between Slang and Slang Terms?

The words that stick around are the words that fill a lexical gap. The word chill and chill acts became like very big in the early to mid 2000s. Freaking out was another one that took a seat at the table to everyday English. And I have a theory that when you're walking down the street and you hear someone yelling really animatedly into the phone, it's not actually what they wanted to say. It's the rehashing of what they want to say later on.