The Oxford Thesaurus An A-Z Dictionary of Synonyms - improvementn.

1) betterment, amelioration; reform, rehabilitation, upgrading, enhancement, repair: The committee is working for the improvement of the neighbourhood. 2) recovery, rise, increase, gain, advance, upswing, progress; recuperation, convalescence: There was an improvement in share prices after release of the trade figures. The patient shows considerable improvement. 3) advance, change for the better: This year's crop is an improvement over last year's.