Ferrous, in chemical science, indicates a bivalent iron compound (+2 oxidation state), as opposed to ferric, which indicates a trivalent iron compound (+3 oxidation state). Outside of chemical science, ferrous's an adjective used to indicate the presence of iron. Ferrous metals include steel and pig iron (which contain a few percent of carbon) and alloys of iron with other metals (such as stainless steel.) The term non-ferrous's used to indicate metals other than iron and alloys that don't conta… (More on Ferrous)