Salsa generally means sauce as in English, as well as salad dressing.
salsa agresta: sour grapes with saffron, sugar and breadcrumbs, used with fried foods; now rare (Liguria)
salsa agrodolce: sweet sour sauce
salsa brun: same as salsa spagnola (see below)
salsa inglesa: Worcestershire sauce
salsa di mirtillo: cranberry sauce
salsadi noci: Ligurian walnut sauce, made with walnuts pounded with butter, cream, olive oil, and Parmesan, used on pansotti
salsa olandese: hollandaise sauce
salsa piccante: hot sauce
salsa rosa: cocktail sauce, or mayonnaise with tomatoes and yoghurt.
salsa rubra: ketchup (most Italians now say ketchup, however)
Image by Hans