Chorizo is a pork sausage originating from Spain. It is made from coarsely chopped fatty pork and usually seasoned with chili and paprika. The mild Spanish paprika used is what gives this sausage its characteristic flavor. The paprika itself can be found as either picante (hot) or dulce (sweet). Some varieties are hung in cold dry places to cure, as happens with jamón serrano (ham). The Pamplona variety grinds the meat further.
Chorizo can be eaten as is (sliced or in a sandwich), simmered in sidra, barbecued or fried. Like breakfast sausage, it is used as an ingredient of other dishes. It also can be used as a partial replacement for ground beef or pork. In Argentina and other South American countries, chorizo is the name for any coarse meat sausage. Argentine chorizos normally contain pork meat and do not tend to be terribly spicy.
There is also a Portuguese sausage, also made from pork but with different seasonings, called chouriço.