sleep

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A natural periodic state of rest for the mind and body, in which the eyes usually close and consciousness is completely or partially lost, so that there is a decrease in bodily movement and responsiveness to external stimuli. During sleep the brain in humans and other mammals undergoes a characteristic cycle of brain-wave activity that includes intervals of dreaming.
• noun A period of this form of rest.
• noun A state of inactivity resembling or suggesting sleep; unconsciousness, dormancy, hibernation, or death.
• noun A state in which a computer shuts off or reduces power to its peripherals (such as the display or memory) in order to save energy during periods of inactivity.
• noun Botany The folding together of leaflets or petals at night or in the absence of light.
• noun A crust of dried tears or mucus normally forming around the inner rim of the eye during sleep.
• intransitive verb To be in the state of sleep or to fall asleep.
• intransitive verb To be in a condition resembling sleep.
• intransitive verb To pass or get rid of by sleeping.
• intransitive verb To provide sleeping accommodations for.
• idiom (log/rock) To sleep very deeply.

from The Century Dictionary.

• noun A state of general marked quiescence of voluntary and conscious (as well as many involuntary and unconscious) functions, alternating more or less regularly with periods of activity.
• noun A period of sleep: as, a short sleep.
• noun Repose; rest; quiet; dormancy; hence, the rest of the grave; death.
• noun Specifically, in zoology, the protracted and profound dormancy or torpidity into which various animals fall periodically at certain seasons of the year.
• noun In botany, nyctitropism, or the sleep-movement of plants, a condition brought about in the foliar or floral organs of certain plants, in which they assume at nightfall, or just before, positions unlike those which they have maintained during the day.
• To take the repose or rest which is afforded by a suspension of the voluntary exercise of the bodily functions and the natural suspension, complete or partial, of consciousness; slumber. See the noun.
• To fall asleep; go to sleep; slumber.
• To lie or remain dormant; remain inactive or unused; be latent; be or appear quiet or quiescent; repose quietly: as, the sword sleeps in the scabbard.
• To rest, as in the grave; lie buried.
• To be careless, remiss, inattentive, or unconcerned; live thoughtlessly or carelessly; take things easy.
• In botany, to assume a state, as regards vegetable functions, analogous to the sleeping of animals. See sleep, n., 5.
• To be or become numb through stoppage of the circulation: said of parts of the body. See asleep.
• Synonyms and
• Drowse, Doze, Slumber, Sleep, nap, rest, repose. The first four words express the stages from full consciousness to full unconsciousness in sleep. Sleep is the standard or general word. Drowse expresses that state of heaviness when one does not quite surrender to sleep. Doze expresses the endeavor to take a sort of waking nap. Slumber has largely lost its earlier sense of the light beginning of sleep, and is now more often an elevated or poetical word for sleep.
• To take rest in: with a cognate object, and therefore transitive in form only: as, to sleep the sleep that knows no waking.
• With away: To pass or consume in sleeping: as, to sleep away the hours; to sleep away one's life.
• With off or out: To get rid of or overcome by sleeping; recover from during sleep: as, to sleep off a headache or a debauch.
• To afford or provide sleeping-accommodation for: as, a car or cabin that can sleep thirty persons.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To take rest by a suspension of the voluntary exercise of the powers of the body and mind, and an apathy of the organs of sense; to slumber.
• intransitive verb To be careless, inattentive, or uncouncerned; not to be vigilant; to live thoughtlessly.
• intransitive verb To be dead; to lie in the grave.
• intransitive verb To be, or appear to be, in repose; to be quiet; to be unemployed, unused, or unagitated; to rest; to lie dormant.
• noun A natural and healthy, but temporary and periodical, suspension of the functions of the organs of sense, as well as of those of the voluntary and rational soul; that state of the animal in which there is a lessened acuteness of sensory perception, a confusion of ideas, and a loss of mental control, followed by a more or less unconscious state.
• noun (Bot.) a state of plants, usually at night, when their leaflets approach each other, and the flowers close and droop, or are covered by the folded leaves.
• transitive verb To be slumbering in; -- followed by a cognate object.
• transitive verb rare To give sleep to; to furnish with accomodations for sleeping; to lodge.