microSD

Smaller than miniSD cards, and also based on the SD card format, microSD memory cards measure roughly 15mm x 11mm in size - about the size of a little finger fingernail. This makes them ideal for use in mobile phones. The microSD format was originally developed and sold by SanDisk as the TransFlash format before being adopted in a slightly modified form by the Secure Digital Card Association.
Also known as: "TransFlash"

Memory Stick Pro
Microsoft

Mobile Tech Glossary