Platform Definition In the computer world, a "platform" typically refers to a computer's operating system. For example, a Dell computer running Windows XP would be considered to be running on a Windows platform. An iMac, on the other hand, runs on the Macintosh platform. It is a more generic way of referring to a computer's operating system than having to specify, for example, Windows XP Professional SP 2, or Mac OS X 10.3.5. The term platform is often used when referring to what kind of co...