Source : Webster's Revised Unabridged Dictionary (1913)

Scour \Scour\, v. i.
   1. To clean anything by rubbing. --Shak.

   2. To cleanse anything.

            Warm water is softer than cold, for it scoureth
            better.                               --Bacon.

   3. To be purged freely; to have a diarrh[oe]a.

   4. To run swiftly; to rove or range in pursuit or search of
      something; to scamper.

            So four fierce coursers, starting to the race, Scour
            through the plain, and lengthen every pace.
                                                  --Dryden.

Scour \Scour\ (skour), v. t. [imp. & p. p. {Scoured}; p. pr. &
   vb. n. {Scouring}.] [Akin to LG. sch["u]ren, D. schuren,
   schueren, G. scheuern, Dan. skure; Sw. skura; all possibly
   fr. LL. escurare, fr. L. ex + curare to take care. Cf.
   {Cure}.]
   1. To rub hard with something rough, as sand or Bristol
      brick, especially for the purpose of cleaning; to clean by
      friction; to make clean or bright; to cleanse from grease,
      dirt, etc., as articles of dress.

   2. To purge; as, to scour a horse.

   3. To remove by rubbing or cleansing; to sweep along or off;
      to carry away or remove, as by a current of water; --
      often with off or away.

            [I will] stain my favors in a bloody mask, Which,
            washed away, shall scour my shame with it. --Shak.

   4. [Perhaps a different word; cf. OF. escorre, escourre, It.
      scorrere, both fr. L. excurrere to run forth. Cf.
      {Excursion}.] To pass swiftly over; to brush along; to
      traverse or search thoroughly; as, to scour the coast.

            Not so when swift Camilla scours the plain. --Pope.

   {Scouring barrel}, a tumbling barrel. See under {Tumbling}.
      

   {Scouring cinder} (Metal.), a basic slag, which attacks the
      lining of a shaft furnace. --Raymond.

   {Scouring rush}. (Bot.) See {Dutch rush}, under {Dutch}.

   {Scouring stock} (Woolen Manuf.), a kind of fulling mill.

Scour \Scour\, n.
   Diarrh[oe]a or dysentery among cattle.

Scour \Scour\, v. t.
   To cleanse or clear, as by a current of water; to flush.

         If my neighbor ought to scour a ditch.   --Blackstone.

Scour \Scour\, n.
   1. The act of scouring.

   2. A place scoured out by running water, as in the bed of a
      stream below a fall.

            If you catch the two sole denizens [trout] of a
            particular scour, you will find another pair
            installed in their place to-morrow.   --Grant Allen.

Source : WordNet®

scour
     v 1: examine minutely; "The police scoured the country for the
          fugitive"
     2: clean with hard rubbing; "She scrubbed his back" [syn: {scrub}]
     3: rub hard or scrub; "scour the counter tops" [syn: {abrade}]
     4: rinse, clean, or empty with a liquid; "flush the wound with
        antibiotics"; "purge the old gas tank" [syn: {flush}, {purge}]

scour
     n : a place that is scoured (especially by running water)