The Collaborative International Dictionary of English v.0.48:

Amendment \A*mend"ment\, n. [F. amendement, LL. amendamentum.]
   1. An alteration or change for the better; correction of a
      fault or of faults; reformation of life by quitting vices.
      [1913 Webster]

   2. In public bodies; Any alternation made or proposed to be
      made in a bill or motion by adding, changing,
      substituting, or omitting.
      [1913 Webster]

   3. (Law) Correction of an error in a writ or process.
      [1913 Webster]

   Syn: Improvement; reformation; emendation.
        [1913 Webster]

WordNet (r) 3.0 (2006):

amendment
    n 1: the act of amending or correcting
    2: a statement that is added to or revises or improves a
       proposal or document (a bill or constitution etc.)