: the natural, easily reversible periodic state of many living things that is marked by the absence of wakefulness and by the loss of consciousness of one's surroundings, is accompanied by a typical body posture (such as lying down with the eyes closed), the occurrence of dreaming, and changes in brain activity and physiological functioning, is made up of cycles of non-REM sleep and REM sleep, and is usually considered essential to the restoration and recovery of vital bodily and mental functions
I just need to get some sleep.
How much sleep did you get last night?
Her roommate talks in her sleep.
The noise woke her from a deep sleep.
He woke up and rubbed the sleep out of his eyes. Verb
I couldn't sleep last night. I was awake all night long.
I usually try to sleep for at least eight hours every night.
Did you sleep soundly last night?
We were sleeping peacefully when a sudden loud noise woke us up.
I can never sleep on airplanes.
The tent sleeps five adults. See More
Recent Examples on the Web
Three months of consistent sleep issues is considered insomnia.—Rachel Murphy, Verywell Health, 17 Nov. 2023 Her husband, two of their daughters, their 10-year-old grandson and Lena’s 87-year-old mother-in-law were stretched out in the same room, silently willing themselves into uneasy sleep.—Vivian Yee, New York Times, 17 Nov. 2023 This is the safest sleep position but can result in misshapen heads that are flat on the side or back.—Maria Carter, Parents, 16 Nov. 2023 Researchers used the following checklist to determine how cardiovascular health is connected to aging: diet, physical activity, nicotine exposure, sleep health, BMI, cholesterol, blood sugar, and blood pressure.—Kaitlin Vogel, Health, 15 Nov. 2023 Apply it overnight for moisturized sleep, or use it as a daytime lip gloss alternative for all-day hydration.—Samantha Booth, Rolling Stone, 15 Nov. 2023 The Navy has failed to erase the sleep deprivation problems that have been contributing to deadly and expensive accidents aboard American warships, according to a report by the General Accounting Office, the investigative arm of Congress.—Gary Robbins, San Diego Union-Tribune, 15 Nov. 2023 This absorbing history traces the science of sleep from its origins in a lab at the University of Chicago in the nineteen-twenties.—Condé Nast, The New Yorker, 13 Nov. 2023 Smoking is the most preventable cause of premature death in the U.S.
Get a healthy amount of sleep.—Linda Carroll, NBC News, 6 Nov. 2023
In romantic movies, the couple always falls asleep cuddled together—but in reality, going to sleep is far from bliss for many couples.—Veronica Cristino, Vogue, 21 Nov. 2023 Now is a great time to score a deal on tents, backpacks, sleeping pads, and Garmin devices.—Scott Gilbertson, WIRED, 20 Nov. 2023 In video captured by NBC News’ crew at the Emirates hospital in Rafah, babies lie side by side, some crying out, while others lie sleeping on their backs or curled up in the fetal position.—Chantal Da Silva, NBC News, 20 Nov. 2023 This handy sofa bed pulls out to create a much more comfortable sleeping space than an air mattress.—Matthew Parker, Rolling Stone, 19 Nov. 2023 Instead, many babies develop a flat head from always sleeping on their backs.—Maria Carter, Parents, 16 Nov. 2023 In the video snippet from November 2021, a man approaches a figure who is sleeping on the sidewalk, holding a large canister, sprays him in the face and flees west.—Jesse Barron, New York Times, 16 Nov. 2023 Nahid Abdel Hamid, 26, a mother of three, sleeps nearby.—Hajar Harb, Washington Post, 15 Nov. 2023 As standard, the vessel can sleep up to 10 guests and five crew.—Rachel Cormack, Robb Report, 8 Nov. 2023 See More
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sleep.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Middle English slepe, from Old English slǣp; akin to Old High German slāf sleep and perhaps to Latin labi to slip, slide
First Known Use
before the 12th century, in the meaning defined at sense 1
: the natural, easily reversible, periodic state of many living things that is marked by the absence of wakefulness and by the loss of consciousness of one's surroundings, is accompanied by a typical body posture (as lying down with the eyes closed), the occurrence of dreaming, and changes in brain activity and physiological functioning, is made up of cycles of non-REM sleep and REM sleep, and is usually considered essential to the restoration and recovery of vital bodily and mental functions