DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Burr \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.
      [1913 Webster]