A natural state of rest when your body and mind are not active in the usual way, and you are not aware of what is happening around you. Sleep helps your body repair itself and your brain process information.
“Sleep” comes from Old English “slǣp,” from a very old Germanic root shared with German “Schlaf.” It likely goes back to an Indo‑European root connected with being weak or slipping away. The core meaning of rest and unconsciousness has stayed stable for thousands of years.
Sleep is so basic that nearly every language has an ancient word for it—not a borrowed one. Modern science shows that while you “switch off,” your brain runs an intense overnight cleaning and organizing shift. The word sounds peaceful, but the biology behind it is surprisingly busy.
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