Definition: MultiMedia Card (MMC) is a type of flash memory card used in digital cameras to store data about images. MMC is a slightly older type of flash memory technology, and the more popular Secure Digital (SD) memory card technology is based on MMC. Some digital cameras can use MMC and SD cards interchangeably. MMC cards have a maximum storage capacity of 4GB (gigabytes).
Siemens AG and SanDisk combined to develop MultiMedia Card technology in 1997. MMC cards are slightly rectangular, with one corner cut at a 45-degree angle. MMC cards measure 24 mm by 32 mm by 1.4 mm (0.94 x 1.26 x 0.06 inches).
Reduced-Size MultiMedia Card (RS-MMC) memory cards are available, too, and they're a little more than half the size of an MMC card. RS-MMC cards typically are made for cell phones, rather than digital cameras.
