This again??

I didn't read all the previous posts, but...

Marinara is a sauce... so is pretty much everything else you can make in less than 2 hours. Tomatoes, onions, aromatics (garlic and herbs), whatever else (wine, seasoning), etc. Sauce.

"Gravy" is a low-and-slow sauce, with lots of different meats and heavier veggies added, cooked for hours and hours, and is thick and beautiful.

Both are beautiful, and both have their place.