In a jiff/jiffy
‘In a jiff’ or ‘in a jiffy’ means in a short moment of time, and is a British colloquialism that dates from the late 18th century, the origin of which is unknown. More latterly, from the early 20th century onwards, ‘jiffy’ is used to measure extremely short periods of time, which vary according to the particular field of study. The most well-known one was first proposed by physicist Gilbert Newton Lewis (1875-1946) who defined a ‘jiffy’ as the time it takes light to travel one centimetre. Apart from specialist, scientific definitions like these, ‘jiffy’ remains a popular colloquialism for any short space of time.