Source : Webster's Revised Unabridged Dictionary (1913)

Watch \Watch\ (w[o^]ch), n. [OE. wacche, AS. w[ae]cce, fr.
   wacian to wake; akin to D. wacht, waak, G. wacht, wache.
   [root]134. See {Wake}, v. i. ]
   1. The act of watching; forbearance of sleep; vigil; wakeful,
      vigilant, or constantly observant attention; close
      observation; guard; preservative or preventive vigilance;
      formerly, a watching or guarding by night.

            Shepherds keeping watch by night.     --Milton.

            All the long night their mournful watch they keep.
                                                  --Addison.

   Note: Watch was formerly distinguished from ward, the former
         signifying a watching or guarding by night, and the
         latter a watching, guarding, or protecting by day
         Hence, they were not unfrequently used together,
         especially in the phrase to keep watch and ward, to
         denote continuous and uninterrupted vigilance or
         protection, or both watching and guarding. This
         distinction is now rarely recognized, watch being used
         to signify a watching or guarding both by night and by
         day, and ward, which is now rarely used, having simply
         the meaning of guard, or protection, without reference
         to time.

               Still, when she slept, he kept both watch and
               ward.                              --Spenser.

               Ward, guard, or custodia, is chiefly applied to
               the daytime, in order to apprehend rioters, and
               robbers on the highway . . . Watch, is properly
               applicable to the night only, . . . and it begins
               when ward ends, and ends when that begins.
                                                  --Blackstone.

   2. One who watches, or those who watch; a watchman, or a body
      of watchmen; a sentry; a guard.

            Pilate said unto them, Ye have a watch; go your way,
            make it as sure as ye can.            --Matt. xxvii.
                                                  65.

   3. The post or office of a watchman; also, the place where a
      watchman is posted, or where a guard is kept.

            He upbraids Iago, that he made him Brave me upon the
            watch.                                --Shak.

   4. The period of the night during which a person does duty as
      a sentinel, or guard; the time from the placing of a
      sentinel till his relief; hence, a division of the night.

            I did stand my watch upon the hill.   --Shak.

            Might we but hear . . . Or whistle from the lodge,
            or village cock Count the night watches to his
            feathery dames.                       --Milton.

   5. A small timepiece, or chronometer, to be carried about the
      person, the machinery of which is moved by a spring.

Watch \Watch\, v. i. [Cf. AS. w[oe]ccan, wacian. [root]134. See
   {Watch}, n., {Wake}, v. i. ]
   1. To be awake; to be or continue without sleep; to wake; to
      keep vigil.

            I have two nights watched with you.   --Shak.

            Couldest thou not watch one hour ?    --Mark xiv.
                                                  37.

   2. To be attentive or vigilant; to give heed; to be on the
      lookout; to keep guard; to act as sentinel.

            Take ye heed, watch and pray.         --Mark xiii.
                                                  33.

            The Son gave signal high To the bright minister that
            watched.                              --Milton.

   3. To be expectant; to look with expectation; to wait; to
      seek opportunity.

            My soul waiteth for the Lord more than they that
            watch for the morning.                --Ps. cxxx. 6.

   4. To remain awake with any one as nurse or attendant; to
      attend on the sick during the night; as, to watch with a
      man in a fever.

   5. (Naut.) To serve the purpose of a watchman by floating
      properly in its place; -- said of a buoy.

   {To watch over}, to be cautiously observant of; to inspect,
      superintend, and guard.

Watch \Watch\, v. t. [imp. & p. p. {Watched}; p. pr. & vb. n.
   {Watching}.]
   1. To give heed to; to observe the actions or motions of, for
      any purpose; to keep in view; not to lose from sight and
      observation; as, to watch the progress of a bill in the
      legislature.

            Saul also sent messengers unto David's house to
            watch him, and to slay him.           --1 Sam. xix.
                                                  11

            I must cool a little, and watch my opportunity.
                                                  --Landor.

            In lazy mood I watched the little circles die.
                                                  --Longfellow.

   2. To tend; to guard; to have in keeping.

            And flaming ministers, to watch and tend Their
            earthy charge.                        --Milton.

            Paris watched the flocks in the groves of Ida.
                                                  --Broome.

Source : WordNet®

watch
     n 1: a small portable timepiece [syn: {ticker}]
     2: a period of time (4 or 2 hours) during which some of a
        ship's crew are on duty
     3: a purposeful surveillance to guard or observe [syn: {vigil}]
     4: the period during which someone (especially a guard) is on
        duty
     5: a person employed to watch for something to happen [syn: {lookout},
         {lookout man}, {sentinel}, {sentry}, {spotter}, {scout},
        {picket}]
     6: a devotional watch (especially on the eve of a religious
        festival) [syn: {vigil}]

watch
     v 1: look attentively; "watch a basketball game"
     2: follow with the eyes or the mind; "Keep an eye on the baby,
        please!"; "The world is watching Sarajevo"; "She followed
        the men with the binoculars" [syn: {observe}, {follow}, {watch
        over}, {keep an eye on}]
     3: see or watch; "view a show on television"; "This program
        will be seen all over the world"; "view an exhibition";
        "Catch a show on Broadway"; "see a movie" [syn: {view}, {see},
         {catch}, {take in}]
     4: observe with attention; "They watched as the murderer was
        executed" [syn: {look on}]
     5: be vigilant, be on the lookout, be on one's guard, be
        careful; "Watch out for pickpockets!" [syn: {look out}, {watch
        out}]
     6: observe or determine by looking; "Watch how the dog chases
        the cats away"
     7: find out, learn, or determine with certainty, usually by
        making an inquiry or other effort; "I want to see whether
        she speaks French"; "See whether it works"; "find out if
        he speaks Russian"; "Check whether the train leaves on
        time" [syn: {determine}, {check}, {find out}, {see}, {ascertain},
         {learn}]