This confusing term has two meanings:
1) Originally, an OEM (original equipment manufacturer)REG was a company that supplied equipment to other companies to resell or incorporate into another product using the reseller's brand name. For example, a maker of refrigerators like Frigidaire might sell its refrigerators to a retailer like Sears to resell under a brand name owned by Sears. A number of companies, both equipment suppliers and equipment resellers, still use this meaning.
2) More recently, OEM is used to refer to the company that acquires a product or component and reuses or incorporates it into a new product with its own brand name.
Also see value-added reseller (VAR), a similar term applied to the repackaging of software.