Source : Webster's Revised Unabridged Dictionary (1913)

Reversionary \Re*ver"sion*a*ry\, a. (Law)
   Of or pertaining to a reversion; involving a reversion; to be
   enjoyed in succession, or after the termination of a
   particular estate; as, a reversionary interest or right.

Reversionary \Re*ver"sion*a*ry\, n. (Law)
   That which is to be received in reversion.

Source : WordNet®

reversionary
     adj : of or relating to or involving a reversion (especially a
           legal reversion); "reversionary annuity"; "reversionary
           interest"