A dongle is a small piece of computer hardware that connects to a port on another device to provide it with additional functionality, or enable a pass-through to such a device that adds functionality.
A Bluetooth dongle that enables Bluetooth functionality on a computer without built-in Bluetooth
There are varying accounts on the etymology of the word "dongle"; in a 1999 paper, P. B. Schneck stated that the origin was unclear, but that it was possibly a corruption of the word "dangle" (since these devices "dangle" from a port on a PC).
A 1992 Byte magazine advertisement by Rainbow Technologies claimed that dongles were invented by and named after a person named "Don Gall", which spawned an urban legend. Linguist Ben Zimmer noted that the claim was likely a by-product of their "tongue-in-cheek" marketing style, and "was so egregiously false that the company happily owned up to it as a marketing ploy when pressed by Eric S. Raymond, who maintains the Jargon File, an online lexicon of hacker slang."
Very short cables that connect relatively large jacks to smaller plugs allow cables to be easily installed and removed from equipment with limited space available for connectors. The Chromecast devit negates the need for a short adapter cable.
The Everdrive series of game cartridges has enabled classic systems such as the Sega Mega Drive and Nintendo 64 to allow one cartridge to have a number of games that were formerly on multiple cartridges of their own, by use of an SD card with ROMs on them; since it can allow a real game console to access ROMs, which an emulator would normally do.
The Sega 32X was an add-on for the Sega Megadrive which allowed a 32-bit library of games to play on a system that was normally just 16-bit, though it suffered from having its own AC adapter in order to work.
Older cars that "externalized" their CD players and changers from the head unit can now use "emulators" that allow USB and SD cards with MP3s and other audio files to be recognized as "tracks" to the CD control unit circuitry.
Adapters that convert miniature implementations of an interface to the full-sized equivalent, or are required to provide the electrical and mechanical interfaces for expansion cards that cannot physically accommodate them (such as PCMCIA, Compact Flash and ExpressCard expansion cards which are just millimetres thick, too small for a standard connector without having the connector and housing extend beyond the dimensions specified by the standard). Although commonly referred to as "dongles", the alternative term "Pig-tail" is favoured by some in the IT industry, due to the appearance of a full-sized connection element, with a short, thin wire extending, somewhat reminiscent of the rear of porcine animals. The term is somewhat descriptive, and allows one to avoid using the word dongle except for its original meaning.
^Watson, David Lilburn; Jones, Andrew (2013-08-30). Digital Forensics Processing and Procedures: Meeting the Requirements of ISO 17020, ISO 17025, ISO 27001 and Best Practice Requirements. Newnes. ISBN 9781597497459.
^Lee, Dave (2016-11-07). "Discussing the dongles". BBC News. Retrieved 2019-04-21.
^ abGarber, Megan (2013-07-29). "The Origin of the Word 'Dongle': 7 Leading Theories". The Atlantic. Retrieved 2019-04-21.
^Schneck, P.B. (July 1999). "Persistent access control to prevent piracy of digital information". Proceedings of the IEEE. 87 (7): 1239–1250. doi:10.1109/5.771075.
^Welch, Chris (2016-03-09). "Intel Compute Stick review: Windows 10 for your TV". The Verge. Retrieved 2019-04-21.
^Bohn, Dieter (2016-04-27). "This $70 computer stick is designed for Ubuntu". The Verge. Retrieved 2019-04-21.