Dongle

Dongle (pronounced dong-guhl)

(1) Historically, a hardware device attached to a computer without which a particular software program will not run; used to prevent unauthorized use.

(2) Latterly, a device (almost always plugged into a USB port) to enable connectivity with other devices, peripherals or networks.

(3) In (very) casual use, any small USB device. 

1980: First recorded in 1980, shortly after the debut of the original IBM PC-1 and although often cited as arbitrary coinage, is possibly derived from dangle, given the first dongles dangled from a short cable.  Unfortunately, Rainbow Technologies' advertisement in computer magazines in the early 1990s claiming the dongle was invented by an engineer named Don Gall was just an attempt to make nerds laugh and maybe create an urban legend.  Donglegate was a 2013 incident at an IT conference when a double entendre on the word "dongle" led to a complaint.  Because of the nature of the devices and the use to which they're put, it's surprising it seems not to be used as a verb, dongling & dongled never emerging.  Dongle is a noun; the noun plural is dongles.

Rainbow Technologies' "Don Gale" dongle advertisement (1992).  While there was no actual Mr Gale, the story related is exactly the reason the software protection hardware was created. 

Parallel-port dongle.  KTA Hookup Software may not be what you think.

Historically, a dongle was a small (about the size of a box of matches) pass-through device, a piece of hardware which connected to a PC’s 25-pin parallel (then used most often for a printer) port.  It provided usually a form of copy protection and license enforcement in that the software with which it was supplied wouldn’t run unless dongle was plugged-in.  Most PCs had only one printer port (although from the original IBM PC-1 (1981), there was always support for three physical parallel ports and in the early days of the industry it wasn't unknown to see three Epson 9-pin impact (dot-matrix) printers clattering away, hanging off the one PC) but it was in some cases possible to daisy-chain multiple dongles on the one port and still connect the actual printer (as the last device in the chain).  The parallel-port dongles were famously robust and reliable but less successful were the early implementations of dongles as USB devices, the problems not solved until the early 2000s.

Raspberry Pi Nano WiFi dongle.

Dongle has also come to mean just about anything small which connects to a USB port and does something.  Although the definitions were never codified, the convention of use with USB devices seems to be that a dongle is something which in some way is an enabling device for something else (such as connecting to a WAN, LAN, Wi-Fi or a streaming feed) whereas “stick”, “pen-drive” or “key” is used for something self-contained such as a flash drive.

Personalized mug-shot dongles.

Today, the most familiar “dongles” are the USB flash drives, used for data storage and file transfer, the later a larger scale version of the original “sneaker-net” which described a kind of low-tech “networking” of devices, accomplished by a programmer (wearing sneakers of course), floppy diskettes in hand, walking between machines to copy and write files.  Memories fade but it’s not forgotten just how transformative was the arrival of the USB flash drive.  Although there had been advances in removable storage which meant at least some users were no longer subject to the tyranny of the 1.44 MB floppy diskette, the proprietary devices were expensive and thus relatively rare.  Additionally, the removable media depended on compatible devices existing at each end, something not always possible conveniently to arrange.  On the PCs, the ubiquitous 3½ floppy diskette had shrunk from it 5¼-inch origins but grown from a capacity 180 KB to 1.44 MB and some versions in the 1990s supported 1.8 MB & 2.88 MB but take-up was slow, the BIOS (Basic Input-Output System) support needed by the latter attracting little support from manufacturers.  Thus the enthusiasm which greeted the 16 MB USB flash drives early in the new century; the capacity of these would expand and, by 2024, 2 TB sticks became available with 4 TB prototypes being demonstrated.  That process also attracted the interest of economists who noted that even by the standards of IT hardware, the unit cost reductions have been dramatic: the early 1 GB sticks sold for around US$300 yet by 2024 1 TB (1024 or 1000 GB depending on manufacturer) sticks were advertised at under US$150.  Curiously (and unusually for the industry), just who “invented” the USB flash drive remains contested.