Source : Webster's Revised Unabridged Dictionary (1913)

Jointure \Join"ture\, n. [F. jointure a joint, orig., a joining,
   L. junctura, fr. jungere to join. See {Join}, and cf.
   {Juncture}.]
   1. A joining; a joint. [Obs.]

   2. (Law) An estate settled on a wife, which she is to enjoy
      after husband's decease, for her own life at least, in
      satisfaction of dower.

            The jointure that your king must make, Which with
            her dowry shall be counterpoised.     --Shak.

Jointure \Join"ture\, v. t. [imp. & p. p. {Jointured}; p. pr. &
   vb. n. {Jointuring}.]
   To settle a jointure upon.

Source : WordNet®

jointure
     n 1: (law) an estate secured to a prospective wife as a marriage
          settlement in lieu of a dower [syn: {legal jointure}]
     2: the act of making or becoming a single unit; "the union of
        opposing factions"; "he looked forward to the unification
        of his family for the holidays" [syn: {union}, {unification},
         {uniting}, {conjugation}] [ant: {disunion}]