Stands for "Original Equipment Manufacturer." The term refers to a company that produces hardware to be marketed under another company's brand. For example, if Sony makes monitors marketed by Dell Computers, they might be labeled "Dell", but the OEM is Sony. You can also use the term as a verb, like this: "That Dell monitor over there is OEM'd by Sony." That should impress your friends.
OEM
Meaning of OEM in English
English glossary of computer and Internet terms. Английский глоссарий компьютерных и Интернет терминов. 2012