The Collaborative International Dictionary of English v.0.48:

Second \Sec"ond\, a. [F., fr. L. secundus second, properly,
   following, fr. sequi to follow. See Sue to follow, and cf.
   Secund.]
   1. Immediately following the first; next to the first in
      order of place or time; hence, occurring again; another;
      other.
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            And he slept and dreamed the second time. --Gen.
                                                  xli. 5.
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   2. Next to the first in value, power, excellence, dignity, or
      rank; secondary; subordinate; inferior.
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            May the day when we become the second people upon
            earth . . . be the day of our utter extirpation.
                                                  --Landor.
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   3. Being of the same kind as another that has preceded;
      another, like a prototype; as, a second Cato; a second
      Troy; a second deluge.
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            A Daniel, still say I, a second Daniel! --Shak.
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   Second Adventist. See Adventist.

   Second cousin, the child of a cousin.

   Second-cut file. See under File.

   Second distance (Art), that part of a picture between the
      foreground and the background; -- called also middle
      ground, or middle distance. [R.]

   Second estate (Eng.), the House of Peers.

   Second girl, a female house-servant who does the lighter
      work, as chamber work or waiting on table.

   Second intention. See under Intention.

   Second story, Second floor, in America, the second range
      of rooms from the street level. This, in England, is
      called the first floor, the one beneath being the
      ground floor.

   Second thought or Second thoughts, consideration of a
      matter following a first impulse or impression;
      reconsideration.
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            On second thoughts, gentlemen, I don't wish you had
            known him.                            --Dickens.
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WordNet (r) 3.0 (2006):

second thought
    n 1: thinking again about a choice previously made; "he had
         second thoughts about his purchase" [syn:
         reconsideration, second thought, afterthought,
         rethink]