dongle

A dongle is a small piece of hardware that connects to another device to provide it with additional functionality. In relation to computing, the term is primarily associated with hardware providing a copy protection mechanism for commercial software—in which the dongle must be attached to the system that the software is installed on in order for it to function. The term "dongle" is also associated with similar devices meant to provide additional forms of wireless connectivity to devices (such as Wi-Fi or Bluetooth support), often over USB connections, as well as small form factor digital media players (such as Amazon Fire TV Stick, Chromecast, and Roku Streaming Stick) and personal computers (such as Chromebit and Intel Compute Stick) meant to plug directly into an HDMI input.