dongle
Dongle (noun) means a compact device that connects to an electronic gadget, commonly a computer, changing what it can do — for example a wireless modem, digital media player, software copy-protection device or adapter.
Etymology
Unknown. Likely a descendant of dangle, reflecting that electronic accessories such as computer peripherals often are plugged in via a flexible cable (although wirelessness is also often relevant). Claims that the word comes from a man named "Don Gall" were made up by an advertisement. First usage 1980-1985.