The Collaborative International Dictionary of English v.0.48:

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.
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   2. To purge; as, to scour a horse.
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   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.
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            [I will] stain my favors in a bloody mask,
            Which, washed away, shall scour my shame with it.
                                                  --Shak.
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   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.
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            Not so when swift Camilla scours the plain. --Pope.
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   5. To cleanse or clear, as by a current of water; to flush.

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