Definitions
1.nounA very short, unspecified length of time."I’ll be back in a jiffy."
2.nounA unit of time defined by the frequency of its basic timer – historically, and by convention, 0.01 of a second, but some computer operating systems use other values.
3.nounThe length of an alternating current power cycle (1/60 or 1/50 of a second).
4.nounThe time taken for light to travel a specified distance in a vacuum, usually one centimetre, but sometimes one foot or the width of a nucleon.
5.nounShort for jiffy bag, a padded envelope.