The Collaborative International Dictionary of English v.0.48:

Harrow \Har"row\ (h[a^]r"r[-o]), n. [OE. harowe, harwe, AS.
   hearge; cf. D. hark rake, G. harke, Icel. herfi harrow, Dan.
   harve, Sw. harf. [root]16.]
   1. An implement of agriculture, usually formed of pieces of
      timber or metal crossing each other, and set with iron or
      wooden teeth. It is drawn over plowed land to level it and
      break the clods, to stir the soil and make it fine, or to
      cover seed when sown.
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   2. (Mil.) An obstacle formed by turning an ordinary harrow
      upside down, the frame being buried.
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   Bush harrow, a kind of light harrow made of bushes, for
      harrowing grass lands and covering seeds, or to finish the
      work of a toothed harrow.

   Drill harrow. See under 6th Drill.

   Under the harrow, subjected to actual torture with a
      toothed instrument, or to great affliction or oppression.
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The Collaborative International Dictionary of English v.0.48:

Drill \Drill\, n.
   1. A small trickling stream; a rill. [Obs.]
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            Springs through the pleasant meadows pour their
            drills.                               --Sandys.
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   2. (Agr.)
      (a) An implement for making holes for sowing seed, and
          sometimes so formed as to contain seeds and drop them
          into the hole made.
      (b) A light furrow or channel made to put seed into
          sowing.
      (c) A row of seed sown in a furrow.
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   Note: Drill is used adjectively, or as the first part of a
         compound; as, drill barrow or drill-barrow; drill
         husbandry; drill plow or drill-plow.
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   Drill barrow, a wheeled implement for planting seed in
      drills.

   Drill bow, a small bow used for the purpose of rapidly
      turning a drill around which the bowstring takes a turn.


   Drill harrow, a harrow used for stirring the ground between
      rows, or drills.

   Drill plow, or Drill plough, a sort plow for sowing grain
      in drills.
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