OEM may refer to any of the following:
1. Short for original equipment manufacturer, OEM describes a manufacturer who puts together computers made of other company's parts and then sells the product under its brand name. Good examples of an OEM are ASUS, Dell, Hewlett Packard, and Sony.
An OEM is responsible for supporting the hardware and software that came with the computer. In other words, if there's a problem with the computer or a part needs replaced, you'd contact the OEM and not the product manufacturer or developer.
2. OEM describes software included with new computers, usually on an optical disc such as a CD-ROM. These discs are only available from the manufacturer, and not intended for resale.