The Multimedia Card (MMC) is a flash memory memory card standard. Unveiled in 1997 by Siemens and SanDisk, it is based on Toshiba's NAND-based flash memory, and is therefore much smaller than earlier systems based on Intel NOR-based memory such as Compact Flash. MMC is about the size of a postage stamp: 24mm x 32mm x 1.5mm. MMC originally used a 1-bit serial interface, but newer versions of the specification allow transfers of 4 or sometimes even 8 bits at a time. They have been more or less superseded by SD cards, but still see significant use because MMC cards can be used in any device which supports SD cards.
Typically, an MMC card is used as storage media for a portable device, in a form that can easily be removed for access by a PC.