It's intensely regional (tends to be certain pockets of East Coast Italians, particularly in the Mid-Atlantic area) but not universal by any means. (My own Italian family doesn't use the term.) From what I understand, it's a result of translation issues confusing early Italian immigrants, and it caught on in certain communities. It's often described as "Sunday Gravy", and refers to the big pot of tomato sauce, especially with a lot of meat - meatballs, sausage, beef ribs, etc. - made for the big Sunday evening family gathering.