Source : Webster's Revised Unabridged Dictionary (1913)

Sleep \Sleep\, v. i. [imp. & p. p. {Slept}; p. pr. & vb. n.
   {Sleeping}.] [OE. slepen, AS. sl?pan; akin to OFries. sl?pa,
   OS. sl[=a]pan, D. slapen, OHG. sl[=a]fan, G. schlafen, Goth.
   sl?pan, and G. schlaff slack, loose, and L. labi to glide,
   slide, labare to totter. Cf. {Lapse}.]
   1. 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. --Chaucer.

            Watching at the head of these that sleep. --Milton.

   2. Figuratively:
      (a) To be careless, inattentive, or uncouncerned; not to
          be vigilant; to live thoughtlessly.

                We sleep over our happiness.      --Atterbury.
      (b) To be dead; to lie in the grave.

                Them also which sleep in Jesus will God bring
                with him.                         --1 Thess. iv.
                                                  14.
      (c) To be, or appear to be, in repose; to be quiet; to be
          unemployed, unused, or unagitated; to rest; to lie
          dormant; as, a question sleeps for the present; the
          law sleeps.

                How sweet the moonlight sleep upon this bank!
                                                  --Shak.

Slept \Slept\,
   imp. & p. p. of {Sleep}.

Source : WordNet®

sleep
     v 1: be asleep [syn: {kip}, {slumber}, {log Z's}, {catch some Z's}]
          [ant: {wake}]
     2: be able to accommodate for sleeping; "This tent sleeps six
        people"
     [also: {slept}]

sleep
     n 1: a natural and periodic state of rest during which
          consciousness of the world is suspended; "he didn't get
          enough sleep last night"; "calm as a child in dreamless
          slumber" [syn: {slumber}]
     2: a torpid state resembling sleep
     3: a period of time spent sleeping; "he felt better after a
        little sleep"; "there wasn't time for a nap" [syn: {nap}]
     4: euphemisms for death (based on an analogy between lying in a
        bed and in a tomb); "she was laid to rest beside her
        husband"; "they had to put their family pet to sleep"
        [syn: {rest}, {eternal rest}, {eternal sleep}, {quietus}]
     [also: {slept}]

slept
     See {sleep}