I was watching an episode of Cooking Live while I was on the treadmill today. Sara Moulton had a guest with her who had won a competition for what I would call ragu: tomato-meat sauce with meats cooked in it for a long time. There was a spirited discussion about whether to call the concoction "gravy" or "sauce". Several people, including the prize-winner, call it gravy if there is meat in it; otherwise, it's "sauce". One caller said it was a regional name, but no one was sure. I lived for 18 years in a town with a large Italian population, and never heard them say it was gravy. What's with the use of the term "gravy" for a tomato-based sauce with meat?