salt pork

So named because it is salt-cured, this is a layer of fat (usually with some streaks of lean) that is cut from the pig's belly and sides. Salt pork is often confused with fatback, which is unsalted. It varies in degree of saltiness and often must be blanched to extract excess salt before being used. It's similar to bacon but much fattier and unsmoked. Salt pork can be refrigerated tightly wrapped for up to a month. It's used primarily as a flavoring and is an important ingredient in many dishes throughout New England and the South.

The noun has one meaning:

Meaning #1: fat from the back and sides and belly of a hog carcass cured with salt