Tomato sauce (also known as Neapolitan sauce, salsa roja in Spanish, or salsa di pomodoro in Italian) can refer to many different sauces made primarily from tomatoes, usually to be served as part of a dish, rather than as a condiment. Tomato sauces are common for meat and vegetables, but they are perhaps best known as bases for Mexican salsas or sauces for pasta dishes. Tomatoes have a rich flavor, high water content, soft flesh which breaks down easily, and the right composition to thicken into a sauce when they are cooked (without the need of thickeners such as roux). All of these qualities make them ideal for simple and appealing sauces.
In countries such as the United Kingdom, India, Australia, New Zealand, and South Africa, the term tomato sauce is used to describe a condiment similar to ketchup. In some of these countries, both terms are used for the condiment.
Prepared with tomatoes, or in a tomato sauce.
Of pasta: In a seafood sauce. Of pizza: With seafood topping.
A marinara sauce.