The Collaborative International Dictionary of English v.0.48:

Quicken \Quick"en\, v. i.
   1. To come to life; to become alive; to become vivified or
      enlivened; hence, to exhibit signs of life; to move, as
      the fetus in the womb.
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            The heart is the first part that quickens, and the
            last that dies.                       -- Ray.
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            And keener lightnings quicken in her eye. --Pope.
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            When the pale and bloodless east began
            To quicken to the sun.                --Tennyson.
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   2. To move with rapidity or activity; to become accelerated;
      as, his pulse quickened.
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The Collaborative International Dictionary of English v.0.48:

Quicken \Quick"en\, v. t. [imp. & p. p. quickened; p. pr. &
   vb. n. Quickening.] [AS. cwician. See Quick, a.]
   1. To make alive; to vivify; to revive or resuscitate, as
      from death or an inanimate state; hence, to excite; to,
      stimulate; to incite.
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            The mistress which I serve quickens what's dead.
                                                  --Shak.
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            Like a fruitful garden without an hedge, that
            quickens the appetite to enjoy so tempting a prize.
                                                  -- South.
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   2. To make lively, active, or sprightly; to impart additional
      energy to; to stimulate; to make quick or rapid; to
      hasten; to accelerate; as, to quicken one's steps or
      thoughts; to quicken one's departure or speed.
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   3. (Shipbuilding) To shorten the radius of (a curve); to make
      (a curve) sharper; as, to quicken the sheer, that is, to
      make its curve more pronounced.
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   Syn: To revive; resuscitate; animate; reinvigorate; vivify;
        refresh; stimulate; sharpen; incite; hasten; accelerate;
        expedite; dispatch; speed.
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WordNet (r) 3.0 (2006):

quicken
    v 1: move faster; "The car accelerated" [syn: accelerate,
         speed up, speed, quicken] [ant: decelerate,
         retard, slow, slow down, slow up]
    2: make keen or more acute; "whet my appetite" [syn: whet,
       quicken]
    3: give life or energy to; "The cold water invigorated him"
       [syn: quicken, invigorate]
    4: show signs of life; "the fetus quickened"
    5: give new life or energy to; "A hot soup will revive me";
       "This will renovate my spirits"; "This treatment repaired my
       health" [syn: animate, recreate, reanimate, revive,
       renovate, repair, quicken, vivify, revivify]