I'll be there in a jiffy

[Amadaeus]

i've heard many times that the word jiffy is actually an amount of time, my question is how big or small of an amount of time, or is it merely a period IN time?

[sense4all]

Similar to" two shakes of a lambs tail", It is a small period of time.

[Postdog]

jiffy: n.
1. The duration of one tick of the system clock on your computer (see tick). Often one AC cycle time (1/60 second in the U.S. and Canada, 1/50 most other places), but more recently 1/100 sec has become common. �The swapper runs every 6 jiffies� means that the virtual memory management routine is executed once for every 6 ticks of the clock, or about ten times a second.

2. Confusingly, the term is sometimes also used for a 1-millisecond wall time interval.

3. Even more confusingly, physicists semi-jokingly use �jiffy� to mean the time required for light to travel one foot in a vacuum, which turns out to be close to one nanosecond. Other physicists use the term for the quantum-nechanical lower bound on meaningful time lengths,

4. Indeterminate time from a few seconds to forever. �I'll do it in a jiffy� means certainly not now and possibly never. This is a bit contrary to the more widespread use of the word. Oppose nano. See also Real Soon Now.

[bernardo]

re number 3 above: I've heard that it is the time for light to travel 1 centimetre.

[Quizmonster]

'Jiffy' has meant a short, indeterminate period of time for a quarter of a millennium, so any reference to computer-clocks or the speed of light is a very recent add-on usage!