My father-in-law is constantly using the term: "black and blue" when he orders a steak "rare" in restaurants despite the fact that almost all waiters seem unfamiliar with the term. Naturally I cringe everytime I hear him contemplating steak on the menu. I maybe heard this term twice in 7 years of cooking, but I had no formal training and I wasn't at Lugers. I say this is an antiquated, local slang, similar to "Philadelphia Style" which is used to describe a method of cooking a steak rare, but is not more descriptive than what "rare" should be in the first place. Father-in-law claims it is a term all classically trained French chefs are familiar with (noir et bleu?). I don't think so.