The Collaborative International Dictionary of English v.0.48:

Emend \E*mend"\, v. t. [imp. & p. p. Emended; p. pr. & vb. n.
   Emending.] [L. emendare; e out + menda, mendum, fault,
   blemish: cf. F. ['e]mender. Cf. Amend, Mend.]
   To purge of faults; to make better; to correct; esp., to make
   corrections in (a literary work); to alter for the better by
   textual criticism, generally verbal.

   Syn: To amend; correct; improve; better; reform; rectify. See
        Amend.
        [1913 Webster]

WordNet (r) 3.0 (2006):

emend
    v 1: make improvements or corrections to; "the text was emended
         in the second edition"