The Collaborative International Dictionary of English v.0.48:

Bright \Bright\, a. [OE. briht, AS. beorht, briht; akin to OS.
   berht, OHG. beraht, Icel. bjartr, Goth. ba['i]rhts.
   [root]94.]
   1. Radiating or reflecting light; shedding or having much
      light; shining; luminous; not dark.
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            The sun was bright o'erhead.          --Longfellow.
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            The earth was dark, but the heavens were bright.
                                                  --Drake.
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            The public places were as bright as at noonday.
                                                  --Macaulay.
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   2. Transmitting light; clear; transparent.
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            From the brightest wines
            He 'd turn abhorrent.                 --Thomson.
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   3. Having qualities that render conspicuous or attractive, or
      that affect the mind as light does the eye; resplendent
      with charms; as, bright beauty.
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            Bright as an angel new-dropped from the sky.
                                                  --Parnell.
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   4. Having a clear, quick intellect; intelligent.
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   5. Sparkling with wit; lively; vivacious; shedding
      cheerfulness and joy around; cheerful; cheery.
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            Be bright and jovial among your guests. --Shak.
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   6. Illustrious; glorious.
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            In the brightest annals of a female reign. --Cotton.
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   7. Manifest to the mind, as light is to the eyes; clear;
      evident; plain.
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            That he may with more ease, with brighter evidence,
            and with surer success, draw the bearner on. --I.
                                                  Watts.
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   8. Of brilliant color; of lively hue or appearance.
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            Here the bright crocus and blue violet grew. --Pope.
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   Note: Bright is used in composition in the sense of
         brilliant, clear, sunny, etc.; as, bright-eyed,
         bright-haired, bright-hued.
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   bright side the positive or favorable aspects of a
      situation.

   to look on the bright side to focus the attention on
      favorable aspects of a situation; to minimize attention to
      possible negative or unfavorable factors in a situation.
      [PJC]

   Syn: Shining; splending; luminous; lustrous; brilliant;
        resplendent; effulgent; refulgent; radiant; sparkling;
        glittering; lucid; beamy; clear; transparent;
        illustrious; witty; clear; vivacious; sunny.
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WordNet (r) 3.0 (2006):

bright side
    n 1: a consoling aspect of a difficult situation; "every cloud
         has a silver lining"; "look on the bright side of it" [syn:
         silver lining, bright side]