Title says it all, what is the difference between a fob and a dongle?

I'm talking of course specifically about the two types of hardware that are used to facilitate interfacing with computer systems and software. (This was added to point out how ON TOPIC via the FAQ this question is, after it was closed.)


I love this question. Fob and dongle. (For some reason those words remind me of Miller's Crossing, though i'm probably thinking of fop and dangle.) A fob is, of course, that plastic thing on your keys that locks/unlocks your doors and more. A dongle is that thing that Autodesk makes you hang off the back of your PC to run Autocad or Maya.

As words, fob has been around for centuries while dongle is a more recently made-up word to describe a hardware key. Fob is interesting in that it meant a small pocket, while now we put fobs in pockets with our keys. You can also have a keyring with a fob and a dongle on it, the former to open your car and the latter to open Maya.

Definitions and Links

fob (from Online Etymology Dictionary) n. 1653, "small pocket for valuables," probably related to Low Ger. fobke "pocket," High Ger. fuppe "pocket." Meaning "chain attached to a watch carried in the fob" is from 1885. v. "to cheat," 1583, from obsolete noun fobbe "cheat, trickster" (1393), perhaps from O.Fr. forbe "cheat." Alternative etymology holds that the word is perhaps related to Ger. foppen "to jeer at, make a fool of" (see fop); or from Ger. fuppen, einfuppen to pocket stealthily, which would connect it to fob (n.). To fob (someone) off is first recorded 1597.

fob off (from Yahoo Education) v. To dispose of (goods) by fraud or deception; palm off: fobbed off the zircon as a diamond.

dongle (from Wordnik) n. noun A hardware device that serves as copy protection for certain software by rendering the software inoperable when the device is not plugged into a printer port.


I believe a fob is something that you don't connect to (like HDD RFID access fobs) and dongles are something that physically connects.

In practice I would probably use the words interchangeably though.

  • 2
    That's my understanding as well. I've never seen a dongle that didn't physically connect, but fobs range from RFID to just random passcode generators. Feb 26 '10 at 16:20

It take my usage of "fob" for the original

fob n.
1. a chain attached to a watch for carrying in a waistcoat or packet
2. the tab on a key ring

which is to say it is something that you carry with you.

A "dongle" is a more general term and includes thing that you leave with the machine.

Accordingly, I would include USB thumbdrives among fobs, a difference from the distinction that Josh K proposes.


If Wikipedia is to be believed, a dongle has had many meanings (source ; dictionary). It really depends on in what context you are using. Originally, dongles were used to authenticate software in the days before internet activation. A "fob", when used as shorthand for "key fob", is really anything designed to be put on a keyring (source). When dongles became compatible with USB, they soon began to adopt many of the physical construction methods used by USB thumb drives. That included designing them to fit on a key ring so it act like a "fob" when not in use.

If you want to explore the literal meaning, the word "fob" is used to describe a physical characteristic. The word "dongle" is used to describe a usage of the item. In today's lexicon, a dongle is anything that attaches to something else to give additional functionality to the "non-dongle" device.

When you talk about RFID devices, the "fob" holds the RFID chip (example), and the dongle is the device that scans the device (example).

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