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.
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.
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.
5. To cleanse or clear, as by a current of water; to flush.
If my neighbor ought to scour a ditch. --Blackstone.
[Webster 1913 Suppl.]
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.