The Collaborative International Dictionary of English v.0.48:

One \One\, n.
   1. A single unit; as, one is the base of all numbers.
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   2. A symbol representing a unit, as 1, or i.
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   3. A single person or thing. "The shining ones." --Bunyan.
      "Hence, with your little ones." --Shak.
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            He will hate the one, and love the other. --Matt.
                                                  vi. 24.
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            That we may sit, one on thy right hand, and the
            other on thy left hand, in thy glory. --Mark x. 37.
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   After one, after one fashion; alike. [Obs.] --Chaucer.

   At one, in agreement or concord. See At one, in the
      Vocab.

   Ever in one, continually; perpetually; always. [Obs.]
      --Chaucer.

   In one, in union; in a single whole.

   One and one, One by one, singly; one at a time; one after
      another. "Raising one by one the suppliant crew."
      --Dryden.

   one on one contesting an opponent individually; -- in a
      contest.

   go one on one, to contest one opponent by oneself; -- in a
      game, esp. basketball.
      [1913 Webster +PJC]