for the better

from The Collaborative International Dictionary of English v.0.48

Better \Bet"ter\, n.
   1. Advantage, superiority, or victory; -- usually with of;
      as, to get the better of an enemy.
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   2. One who has a claim to precedence; a superior, as in
      merit, social standing, etc.; -- usually in the plural.
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            Their betters would hardly be found.  --Hooker.
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   {For the better}, in the way of improvement; so as to produce
      improvement. "If I have altered him anywhere for the
      better." --Dryden.
      [1913 Webster]