What makes something marinara?

Variations include capers, olives, spices and a dash of wine. Marinara sauce is a quick sauce, seasoned only with garlic, chopped red pepper and basil. It's best when made with whole San Marzano tomatoes or plums, shredded by hand or passed through a food mill. The marinara can be left in pieces; the texture of the finished sauce is quite loose and the flavor is that of fresh tomatoes.