The Collaborative International Dictionary of English v.0.48:

Residuary \Re*sid"u*a*ry\ (-?-r?), a. [See Residue.]
   Consisting of residue; as, residuary matter; pertaining to
   the residue, or part remaining; as, the residuary advantage
   of an estate. --Ayliffe.
   [1913 Webster]

   Residuary clause (Law), that part of the testator's will in
      which the residue of his estate is disposed of.

   Residuary devise (Law), the person to whom the residue of
      real estate is devised by a will.

   Residuary legatee (Law), the person to whom the residue of
      personal estate is bequeathed.
      [1913 Webster]

WordNet (r) 3.0 (2006):

residuary
    adj 1: entitled to the residue of an estate (after payment of
           debts and specific gifts); "the residuary part of the
           estate"; "the residuary beneficiary"
    2: relating to or indicating a remainder; "residual quantity"
       [syn: residual, residuary]