Merriam-Webster's Collegiate® Dictionary, 11th Edition
SLEEP
I. noun
Etymology: Middle English slepe, from Old English slǣp; akin to Old High German slāf sleep and perhaps to Latin labi to slip, slide Date: before 12th century the natural periodic suspension of consciousness during which the powers of the body are restored, a state resembling sleep: as, a state of torpid inactivity, death , the closing of leaves or petals especially at night, a state marked by a diminution of feeling followed by tingling , the state of an animal during hibernation,
3. a period spent sleeping, night , a day's journey, crusty matter present in the corner of an eye upon awakening, sleeplike adjective
II. verb (slept; sleeping) Date: before 12th century 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, transitive verb to be slumbering in , to get rid of or spend in or by sleep , to provide sleeping accommodations for