Source : Webster's Revised Unabridged Dictionary (1913)

Burl \Burl\, v. t. [imp. & p. p. {Burled}; p. pr. & vb. n.
   {Burling}.] [OE. burle stuffing, or a knot in cloth; cf. F.
   bourlet, bourrelet, OF. bourel, a wreath or a roll of cloth,
   linen, or leather, stuffed with flocks, etc., dim. of bourre.
   [root]92. See {Bur}.]
   To dress or finish up (cloth); to pick knots, burs, loose
   threads, etc., from, as in finishing cloth.

   {Burling iron}, a peculiar kind of nippers or tweezers used
      in burling woolen cloth.

Burl \Burl\, n.
   1. A knot or lump in thread or cloth.

   2. An overgrown knot, or an excrescence, on a tree; also,
      veneer made from such excrescences.

Source : WordNet®

burl
     n 1: the wood cut from a tree burl or outgrowth; often used
          decoratively in veneer
     2: a large rounded outgrowth on the trunk or branch of a tree
     3: soft lump or unevenness in a yarn; either an imperfection or
        created by design [syn: {slub}, {knot}]
     v : remove the burls from cloth