- (computing) A unit of time defined by the frequency of its basic timer; historically, and by convention, 0.01 seconds, but some operating systems use other values.
- (colloquial) A very short, unspecified length of time.
"I'll be back in a jiffy."
- (physics) The time taken for light to travel one centimetre in a vacuum (sometimes one foot, or sometimes the width of a nucleon)
- (electronics) The length of an alternating current power cycle (1/60 or 1/50 of a second)