miniSD - definition
A memory card is a flash memory data storage device used in a wide range of digital devices such as mobile phones, digital cameras, PDAs, music players, etc. They are small, rugged and offer high re-record ability and power-free operation.
There is a wide range of memory card formats, miniSD (SD stand for Secure Digital) being one of them. It's now considered an outdated standard and in the current generation of portable devices has been replaced by the microSD and microSDHC formats.