The Collaborative International Dictionary of English v.0.48:

Anacoluthon \An`a*co*lu"thon\, n. [Gr. ?, ?, not following,
   wanting sequence; 'an priv. + ? following.] (Gram.)
   A lack of grammatical sequence or coherence in a sentence; an
   instance of a change of construction in a sentence so that
   the latter part does not syntactically correspond with the
   first part.

   Syn: anacoluthia
        [1913 Webster]

WordNet (r) 3.0 (2006):

anacoluthon
    n 1: an abrupt change within a sentence from one syntactic
         structure to another [syn: anacoluthia, anacoluthon]