The Collaborative International Dictionary of English v.0.48:

Messuage \Mes"suage\ (?; 48), n. [Cf. OF. mesuage, masnage, LL.
   messuagium, mansionaticum, fr. L. mansio, -onis, a staying,
   remaining, dwelling, fr. manere, mansum, to stay, remain, E.
   mansion, manse.] (Law)
   A dwelling house, with the adjacent buildings and curtilage,
   and the adjoining lands appropriated to the use of the
   household. --Cowell. Bouvier.
   [1913 Webster]

         They wedded her to sixty thousand pounds,
         To lands in Kent, and messuages in York. --Tennyson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

messuage
    n 1: (law) a dwelling house and its adjacent buildings and the
         adjacent land used by the household