Coined in the 1960s to describe slide shows bundled with audiocassettes, the term MultiMedia is used to describe anything that uses several media.

Current usage in the computer world uses MultiMedia to describe any device capiable of presenting several media (text, video, audio, etc) simultanously, software for use in presenting this media or the media themselves. MIME is typically the way these media are described.

MultiMedia IS NOT used in relation to data storage devices (although these are technically media too).