The Collaborative International Dictionary of English v.0.48:

Synchronize \Syn"chro*nize\, v. i. [imp. & p. p. Synchronized;
   p. pr. & vb. n. Synchronizing.] [Gr. ?.]
   To agree in time; to be simultaneous.
   [1913 Webster]

         The path of this great empire, through its arch of
         progress, synchronized with that of Christianity. --De
                                                  Quincey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

synchronizing
    n 1: the relation that exists when things occur at the same
         time; "the drug produces an increased synchrony of the
         brain waves" [syn: synchronism, synchrony,
         synchronicity, synchroneity, synchronization,
         synchronisation, synchronizing] [ant: asynchronism,
         asynchrony, desynchronisation, desynchronization,
         desynchronizing]
    2: an adjustment that causes something to occur or recur in
       unison [syn: synchronization, synchronisation,
       synchronizing, synchronising]
    3: coordinating by causing to indicate the same time; "the
       synchronization of their watches was an important
       preliminary" [syn: synchronization, synchronisation,
       synchronizing]