An original equipment manufacturer (OEM) generally refers to a company that produces parts and equipment that may be marketed by another manufacturer. However, the term is ambiguous, with several other common meanings. It sometimes means the maker of a system that includes other companies' subsystems, an end-product producer, an automotive part that is manufactured by the same company that produced the original part used in the automobile's assembly, or a value-added reseller.[1][2]
Many customers, such as the Department of Defense, wanted to buy complete systems, all put together and ready to run with the turn of a key; hence the rise of companies known as original equipment manufacturers, or OEMs—they'd buy gear from various companies and put it together in packages.