Source : Webster's Revised Unabridged Dictionary (1913)

Postposition \Post`po*si"tion\, n. [Cf. F. postposition. See
   {Postpone}.]
   1. The act of placing after, or the state of being placed
      after. ``The postposition of the nominative case to the
      verb.'' --Mede.

Source : WordNet®

postposition
     n : (linguistics) the placing of one linguistic element after
         another (as placing a modifier after the word that it
         modifies in a sentence or placing an affix after the base
         to which it is attached)