The Collaborative International Dictionary of English v.0.48:

Wad \Wad\, n. [Probably of Scand. origin; cf. Sw. vadd wadding,
   Dan vat, D. & G. watte. Cf. Wadmol.]
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   1. A little mass, tuft, or bundle, as of hay or tow.
      --Holland.
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   2. Specifically: A little mass of some soft or flexible
      material, such as hay, straw, tow, paper, or old rope
      yarn, used for retaining a charge of powder in a gun, or
      for keeping the powder and shot close; also, to diminish
      or avoid the effects of windage. Also, by extension, a
      dusk of felt, pasteboard, etc., serving a similar purpose.
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   3. A soft mass, especially of some loose, fibrous substance,
      used for various purposes, as for stopping an aperture,
      padding a garment, etc.
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   Wed hook, a rod with a screw or hook at the end, used for
      removing the wad from a gun.
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