WordNet (r) 3.0 (2006):

synchronisation
    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]