reversioner

from WordNet (r) 3.0 (2006)

reversioner
    n 1: (law) a party who is entitled to an estate in reversion

from The Collaborative International Dictionary of English v.0.48

Reversioner \Re*ver"sion*er\, n. (Law)
   One who has a reversion, or who is entitled to lands or
   tenements, after a particular estate granted is terminated.
   --Blackstone.
   [1913 Webster]

from Bouvier's Law Dictionary, Revised 6th Ed (1856)

REVERSIONER, estates. One entitled to a reversion.
     2. Although not in actual possession, the reversioner having a vested 
interest in the reversion, is entitled to his action for an injury done to 
the inheritance. 4 Burr. 2141. The reversioner is entitled to the rent, and 
this important incident passes with a grant or assignment of the reversion. 
It is not inseparable from it, and may be severed and excepted out of the 
grant by special words. Co. Litt. 143, a, 151, a, b Cruise, Digest, t. 17, 
s. 19.