1. a word describing kids with attitude.
2. a rockish scene. (the new emo)
3. mainly used as an adjective for something amazing, awesome, thought provoking, or nonconforming.
1. dude, that girl just walked out of class! she is soo ATT.
2. oh my god, that haircut is so fucking ATT! what a badass.
3. adj; that is one ATT guitar.