The Collaborative International Dictionary of English v.0.48:

Reversion \Re*ver"sion\ (r[-e]*v[~e]r"sh[u^]n), n. [F.
   r['e]version, L. reversio a turning back. See Revert.]
   1. The act of returning, or coming back; return. [Obs.]
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            After his reversion home, [he] was spoiled, also, of
            all that he brought with him.         --Foxe.
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   2. That which reverts or returns; residue. [Obs.]
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            The small reversion of this great navy which came
            home might be looked upon by religious eyes as
            relics.                               --Fuller.
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   3. (Law) The returning of an estate to the grantor or his
      heirs, by operation of law, after the grant has
      terminated; hence, the residue of an estate left in the
      proprietor or owner thereof, to take effect in possession,
      by operation of law, after the termination of a limited or
      less estate carved out of it and conveyed by him. --Kent.
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   4. Hence, a right to future possession or enjoyment;
      succession.
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            For even reversions are all begged before. --Dryden.
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   5. (Annuities) A payment which is not to be received, or a
      benefit which does not begin, until the happening of some
      event, as the death of a living person. --Brande & C.
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   6. (Biol.) A return towards some ancestral type or character;
      atavism.
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   Reversion of series (Alg.), the act of reverting a series.
      See To revert a series, under Revert, v. t.
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