Definition: Secure Digital High Capacity (SDHC) is a type of flash memory card used in digital cameras to store data about images. SDHC is an improvement on the popular SD memory card technology. SD cards are limited to 2GB (gigabytes) in capacity, while SDHC can store between 4GB and 32GB.
Because of the change in the technology, some older digital cameras that use SD cards cannot read the SDHC cards. SDHC cards include an "HC" in the Secure Digital logo.
The SDHC card standard appeared in 2006, and SDHC cards are similar in size to SD cards, which are slightly rectangular with one corner cut at a 45-degree angle. SDHC cards measure 24 mm by 32 mm by 2.1 mm (0.94 x 1.26 x 0.08 inches).
Another format, called Secure Digital Extended Capacity (SDXC), was introduced in 2009, and it calls for cards with storage capacities up to 2TB (terabytes), or 2,000GB.
