Tomato sauce can refer to many different sauces made primarily from tomatoes

Food 101

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 sauces for Mexican salsas and Italian 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 stewed without the need for thickeners such as roux or masa. All of these qualities make them ideal for simple and appealing sauces.