Source : Webster's Revised Unabridged Dictionary (1913)

Synchrony \Syn"chro*ny\, n.
   The concurrence of events in time; synchronism. [R.]

         Geological contemporaneity is the same as chronological
         synchrony.                               --Huxley.

Source : WordNet®

synchrony
     n : the relation that exists when things occur at the same time;
         "the drug produces an increased synchrony of the brain
         waves" [syn: {synchronism}, {synchronicity}, {synchroneity},
          {synchronization}, {synchronisation}, {synchronizing}]
         [ant: {asynchronism}, {asynchronism}, {asynchronism}]