GG - Nah! Not Really ... A quick Wikipedia search reveals that:
Dongle was used by the late Peter Sellers in an episode of the BBC Goon Show radio series, The Vanishing Room from December 1957. The whole sentence is "Flip my dongle and lower my grobblers" as an expression of surprise.
From which I deduce that a dongle typically dangles ... (and I'm not going any further down this particular road!)
I dimly recall using the first HP Programmable Calculator (a Model 85) sometime in the 60's in which some professional engineering programme would only run if you inserted a dongle into the serial port. It made sure that only the licensed user who physically possessed the dongle could use the programme! It was also a bl**dy nuisance because you could only print via the serial port - so you had to take the dongle out - and then the bl**dy programme didn't work. Doh! Eventually they came out with a pass thru dongle which sort of worked.
My definition of a dongle would be something that hangs off a computer (either via a serial port or - more commonly these days - via a USB port) that enables some functionality in the computer but doesn't do anything by itself when unplugged from the computer.
So, sorry, imho your camera doesn't qualify since it does have a function when not connected to the computer.
Actually, I personally find the word "dongle" vaguely quaint and archaic - dating back to an age when you actually needed to programme a computer to do what you wanted it to do each and every time you switched it on (which I guess is also somewhat quaint and archaic).