An SD card, also known as a Secure Digital Memory Card, is a small data storage device used in cell phones, digital cameras and other mobile electronics. They are popular due to their fast rate of memory storage. The term SD card encompasses a few different types of cards.
MiniSD and MicroSD cards are more compact, but can plug into regular SD card readers with the use of a commonly available adapter. The SDHC (High Capacity) card and the SDXC (Extended Capacity) card are more commonly used with video due to their extended capacity for storage. An SDHC card cannot be plugged into a regular SD port, but a regular SD card can be plugged into an SDHC reader. Additionally, an SDXC card is compatible with a SDHC reader.