If you’re taking “forty winks,” you’re having a nap. The implication is that you’re lying in the closed-eye position, the “extended wink” assumed during sleep, but that you don’t fall into a deep sleep.
The phrase “forty winks” can be traced back to Dr. Kitchiner’s 1821 self-help guide, The Art of Invigorating and Prolonging Life. In a November 1821 issue of the British Literary Chronicle, is a review of Kitchiner’s book, which says in part, “Sleep is a subject on which our author acknowledges his feelings are tremblingly alive; he is fond of a ‘forty-winks’ nap in an horizontal posture, as the best preparative for any extraordinary exertion, either of body or mind.”
Well, I can go along with that. But if you didn’t sleep a wink, you got almost no sleep at all. Yet catching 40 winks means having a brief nap. So where does the 40 come from?
How Did It Begin? by R. Brasch (1966) has a whole section on the number 40. “Once it was believed that there was magic in figures and the number 40 especially was thought to possess supernatural powers.”
The use of 40 in this phrase may follow from the old tradition of using 40 to designate an indefinite number as in Shakespeare’s Coriolanus: “I could beat forty of them.” Also, Cassell’s Dictionary of Slang gives ‘many’ as a slang definition of “forty” dating from the mid-1800s.
So the terms “40 winks” and “cat nap” have been common since the 1820s, according to Stuart Berg Flexner. But “wink” has been associated with sleep since the 1300s.
It seems to be accepted that forty winks is just exactly the right amount of sleep, whether it’s five minutes or forty minutes. F. Scott Fitzgerald, in a short article published in the Saturday Evening Post on March 15, 1924, has the main protagonist, Roger Halsey, say to his wife, Gretchen, “Just take forty winks, and when you wake up everything’ll be fine.”
I love catching 40 winks. They’re so soft and delicious, just like chocolate.