Originally slang for a plug-in module to copy protect software (see
hardware key), the term is used for any small module that plugs in and sticks out of a socket; for example, USB flash memory drives and other USB devices such as a wireless mouse receiver or cellular air card. If it uses a very short cable, it may still be called a dongle. See
HDMI dongle,
cellular dongle,
PC Card dongle and
USB drive.