Burr n.  Bot.
 1. A prickly seed vessel. See Bur, 1.
 2. The thin edge or ridge left by a tool in cutting or shaping metal, as in turning, engraving, pressing, etc.; also, the rough neck left on a bullet in casting.
    The graver, in plowing furrows in the surface of the copper, raises corresponding ridges or burrs.   --Tomlinson.
 3. A thin flat piece of metal, formed from a sheet by punching; a small washer put on the end of a rivet before it is swaged down.
 4. A broad iron ring on a tilting lance just below the gripe, to prevent the hand from slipping.
 5. The lobe or lap of the ear.
 6.  A guttural pronounciation of the letter r, produced by trilling the extremity of the soft palate against the back part of the tongue; rotacism; -- often called the Newcastle burr, Northumberland burr, or Tweedside burr.
 7. The knot at the bottom of an antler. See Bur, n., 8.