The Collaborative International Dictionary of English v.0.48:

Between \Be*tween"\, prep. [OE. bytwene, bitweonen, AS.
   betwe['o]nan, betwe['o]num; prefix be- by + a form fr. AS.
   tw[=a] two, akin to Goth. tweihnai two apiece. See Twain,
   and cf. Atween, Betwixt.]
   1. In the space which separates; betwixt; as, New York is
      between Boston and Philadelphia.
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   2. Used in expressing motion from one body or place to
      another; from one to another of two.
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            If things should go so between them.  --Bacon.
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   3. Belonging in common to two; shared by both.
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            Castor and Pollux with only one soul between them.
                                                  --Locke.
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   4. Belonging to, or participated in by, two, and involving
      reciprocal action or affecting their mutual relation; as,
      opposition between science and religion.
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            An intestine struggle, open or secret, between
            authority and liberty.                --Hume.
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   5. With relation to two, as involved in an act or attribute
      of which another is the agent or subject; as, to judge
      between or to choose between courses; to distinguish
      between you and me; to mediate between nations.
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   6. In intermediate relation to, in respect to time, quantity,
      or degree; as, between nine and ten o'clock.
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   Between decks, the space, or in the space, between the
      decks of a vessel.

   Between ourselves, Between you and me, Between
   themselves, in confidence; with the understanding that the
      matter is not to be communicated to others.
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   Syn: Between, Among.

   Usage: Between etymologically indicates only two; as, a
          quarrel between two men or two nations; to be between
          two fires, etc. It is however extended to more than
          two in expressing a certain relation.

                I . . . hope that between public business,
                improving studies, and domestic pleasures,
                neither melancholy nor caprice will find any
                place for entrance.               --Johnson.
          [1913 Webster] Among implies a mass or collection of
          things or persons, and always supposes more than two;
          as, the prize money was equally divided among the
          ship's crew.
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