If you're a physicist, can you run an errand and be back in a jiffy? Well...not unless you can move faster than the speed of light!
Jiffy has been used informally since at least 1785 to mean a very short time. No one knows where the word originally came from. Some sources suggest it may have been a word for "lightning" in the slang used by thieves at the time.
Despite its lowly beginnings, jiffy gained a certain status in the 20th century as a unit of measurement in the scientific world.
This trend started with American chemist Gilbert Newton Lewis in the first half of the 20th century. He suggested using the term jiffy to represent the time it takes for light to travel one centimetre—0.000000000033 seconds, or 33 trillionths of a second.
Since then, various sciences have adopted the jiffy, with differing definitions:
As you can see, a jiffy in scientific circles represents a very small unit of time indeed—the merest fraction of a second! Scientifically speaking, you can't do anything in a jiffy, no matter how fast you are!