When you walk into a salon, you’ll probably overhear a number of terms that sound like a completely different language, or the secret code of an elite club, at the very least. Fear not: we happen to know incredible interpreter, of the celebrity hairstylist variety. We called up Rita Hazan—who has tousled the tresses of superstars like Beyonce and Katy Perry—and asked her to teach us laypeople a lesson in hair color terminology.