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noun \ˈslēp\

: the natural state of rest during which your eyes are closed and you become unconscious

: a period of sleep especially of a particular kind

: the dry substance that sometimes forms in the corners of your eyes while you are sleeping

Full Definition of SLEEP

:  the natural periodic suspension of consciousness during which the powers of the body are restored — compare REM sleep, slow-wave sleep
:  a state resembling sleep: as
a :  a state of torpid inactivity
b :  death <put a pet cat to sleep>; also :  trance, coma
c :  the closing of leaves or petals especially at night
d :  a state marked by a diminution of feeling followed by tingling <my foot's gone to sleep>
e :  the state of an animal during hibernation
a :  a period spent sleeping
b :  night
c :  a day's journey
:  crusty matter present in the corner of an eye upon awakening
sleep·like \-ˌlīk\ adjective

Examples of SLEEP

  1. I just need to get some sleep.
  2. How much sleep did you get last night?
  3. Her roommate talks in her sleep.
  4. The noise woke her from a deep sleep.
  5. He woke up and rubbed the sleep out of his eyes.

Origin of SLEEP

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 12th century

Other Physiology Terms

eructation, flux, gustatory, menarche, myopia, senescence, torpor



: to rest your mind and body by closing your eyes and becoming unconscious

: to have enough space for (a specified number of people) to sleep in it

slept \ˈslept\ sleep·ing

Full Definition of SLEEP

intransitive verb
:  to rest in a state of sleep
:  to be in a state (as of quiescence or death) resembling sleep
:  to have sexual relations —usually used with with
transitive verb
:  to be slumbering in <slept the sleep of the dead>
:  to get rid of or spend in or by sleep <sleep away the hours> <sleep off a headache>
:  to provide sleeping accommodations for <the boat sleeps six>

Examples of SLEEP

  1. I couldn't sleep last night. I was awake all night long.
  2. I usually try to sleep for at least eight hours every night.
  3. Did you sleep soundly last night?
  4. We were sleeping peacefully when a sudden loud noise woke us up.
  5. I can never sleep on airplanes.
  6. The tent sleeps five adults.

First Known Use of SLEEP

before 12th century
SLEEPS Defined for Kids


verb \ˈslēp\
slept \ˈslept\sleep·ing

Definition of SLEEP for Kids

:  to rest with eyes closed in a temporary state of inactivity :  be or lie in a state of sleep <The baby is sleeping.>



Definition of SLEEP for Kids

:  a natural temporary state of rest during which an individual becomes physically inactive and unaware of the surrounding environment and many bodily functions (as breathing) slow
:  an inactive state (as hibernation) like true sleep
:  death 3 <The sick pet was put to sleep.>
sleep·less \-ləs\ adjective
sleep·less·ness noun


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