USB flash drive Definition A USB flash drive -- also known as a USB stick, USB thumb drive or pen drive -- is a plug-and-play portable storage device that uses flash memory and is lightweight enough to attach to a keychain. A USB flash drive can be used in place of a compact disc. When a user plugs the flash memory device into the USB port, the computer's operating system (OS) recognizes the device as a removable drive and assigns it a drive letter. A USB flash drive can store important fi...

Secure Digital card (SD card) A Secure Digital (SD) card is a tiny flash memory card designed for high-capacity memory and various portable devices, such as car navigation systems, cellular phones, e-books, PDAs, smartphones, digital cameras, music players, digital video camcordersand personal computers. In 1999, SanDisk Corp., Panasonic Corp. (formerly known as Matsushita Electric Industrial Co. Ltd.) and Toshiba Corp. agreed to develop and market the Secure Digital card standard, their i...