I do NOT call red sauce "gravy". Gravy is the brown stuff you put on chicken and turkey.
When you see the stuff on the shelf, it says "tomato sauce". Not "tomato gravy".
Take my advice, then. Stay out of South Philadelphia. You call it
sauce down there, you'll be run out of town on a rail, EYE-talian or not!
All good South Philadelphia Italians know that red stuff you put on pasta is
gravy.