NOUN (2)

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.);

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]

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "amendment":
   Great Leap Forward, addendum, addition, advance, advancement,
   alteration, amelioration, ascent, attachment, bettering,
   betterment, bill, boost, calendar, change, change of allegiance,
   change of heart, change of mind, clause, companion bills amendment,
   correction, dragnet clause, editing, emendation, enacting clause,
   enhancement, enrichment, escalator clause, eugenics, euthenics,
   furtherance, headway, hold-up bill, improvement, joker, lift,
   melioration, mend, mending, motion, new birth, omnibus bill,
   paragraph, pickup, preferment, privileged question, progress,
   progression, promotion, proviso, question, rebirth, recension,
   reclamation, recovery, recrudescence, rectification, redaction,
   redemption, reform, reformation, regeneration, renascence, renewal,
   repair, rescript, rescription, restoration, revampment, revisal,
   revise, revised edition, revision, revival, rewrite, rewriting,
   rider, rise, saving clause, upbeat, uplift, upping, upswing,
   uptrend, upward mobility