Source : Webster's Revised Unabridged Dictionary (1913)

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.

   2. Used in expressing motion from one body or place to
      another; from one to another of two.

            If things should go so between them.  --Bacon.

   3. Belonging in common to two; shared by both.

            Castor and Pollux with only one soul between them.
                                                  --Locke.

   4. Belonging to, or participated in by, two, and involving
      reciprocal action or affecting their mutual relation; as,
      opposition between science and religion.

            An intestine struggle, open or secret, between
            authority and liberty.                --Hume.

   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.

   6. In intermediate relation to, in respect to time, quantity,
      or degree; as, between nine and ten o'clock.

   {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.

   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.
          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.

Between \Be*tween"\, n.
   Intermediate time or space; interval. [Poetic & R.] --Shak.

Source : WordNet®

between
     adv 1: in the interval; "dancing all the dances with little rest
            between" [syn: {betwixt}]
     2: in between; "two houses with a tree between" [syn: {'tween}]