The Collaborative International Dictionary of English v.0.48:

Better \Bet"ter\, a.; compar. of Good. [OE. betere, bettre, and
   as adv. bet, AS. betera, adj., and bet, adv.; akin to Icel.
   betri, adj., betr, adv., Goth. batiza, adj., OHG. bezziro,
   adj., baz, adv., G. besser, adj. and adv., bass, adv., E.
   boot, and prob. to Skr. bhadra excellent. See Boot
   advantage, and cf. Best, Batful.]
   1. Having good qualities in a greater degree than another;
      as, a better man; a better physician; a better house; a
      better air.
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            Could make the worse appear
            The better reason.                    --Milton.
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   2. Preferable in regard to rank, value, use, fitness,
      acceptableness, safety, or in any other respect.
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            To obey is better than sacrifice.     --1 Sam. xv.
                                                  22.
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            It is better to trust in the Lord than to put
            confidence in princes.                --Ps. cxviii.
                                                  9.
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   3. Greater in amount; larger; more.
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   4. Improved in health; less affected with disease; as, the
      patient is better.
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   5. More advanced; more perfect; as, upon better acquaintance;
      a better knowledge of the subject.
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   All the better. See under All, adv.

   Better half, an expression used to designate one's wife.
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            My dear, my better half (said he),
            I find I must now leave thee.         --Sir P.
                                                  Sidney.
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   To be better off, to be in a better condition.

   Had better. (See under Had).

   Note: The phrase had better, followed by an infinitive
         without to, is idiomatic. The earliest form of
         construction was "were better" with a dative; as, "Him
         were better go beside." (--Gower.) i. e., It would be
         better for him, etc. At length the nominative (I, he,
         they, etc.) supplanted the dative and had took the
         place of were. Thus we have the construction now used.
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               By all that's holy, he had better starve
               Than but once think this place becomes thee not.
                                                  --Shak.
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