The Collaborative International Dictionary of English v.0.48:

Agglutination \Ag*glu`ti*na"tion\, n. [Cf. F. agglutination.]
   1. The act of uniting by glue or other tenacious substance;
      the state of being thus united; adhesion of parts.
      [1913 Webster]

   2. (Physiol.) Combination in which root words are united with
      little or no change of form or loss of meaning. See
      Agglutinative, 2.
      [1913 Webster]

WordNet (r) 3.0 (2006):

agglutination
    n 1: a clumping of bacteria or red cells when held together by
         antibodies (agglutinins)
    2: the building of words from component morphemes that retain
       their form and meaning in the process of combining
    3: the coalescing of small particles that are suspended in
       solution; these larger masses are then (usually) precipitated
       [syn: agglutination, agglutinating activity]