1. [n]  small bit used in dentistry or surgery
2. [n]  rough projection left on a workpiece after drilling or cutting
3. [n]  rotary file for smoothing rough edges left on a workpiece
4. [n]  United States politician who served as Vice President under Jefferson; he mortally wounded his political rival Alexander Hamilton in a duel and fled south (1756-1836)
5. [n]  seed vessel having hooks or prickles
6. [v]  remove the burrs from

BURR is a 4 letter word that starts with B.

1. \Burr\, n. [See {Bur}.] (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. [Probably of imitative origin.] 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, Northumberland, or
      Tweedside, burr.
   
   7. The knot at the bottom of an antler. See {Bur}, n., 8.
   
   

2. \Burr\, v. i. [imp. & p. p. {Burred}; p. pr. & vb. n.
   {Burring}.]
   To speak with burr; to make a hoarse or guttural murmur.
   --Mrs. Browning.