The Collaborative International Dictionary of English v.0.48:

staple \sta"ple\, v. t. [imp. & p. p. stapled (-p'ld); p. pr.
   & vb. n. stapling.]
   1. To sort according to its staple; as, to staple cotton.
      [1913 Webster]

   2. To fasten together with a staple[9] or staples; as, to
      staple a check to a letter.
      [PJC]