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):

synchronized
    adj 1: operating in unison; "the synchronized flapping of a
           bird's wings" [syn: synchronized, synchronised]

Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "synchronized":
   accordant, according, affirmative, agreeable, agreeing, aligned,
   answerable, arranged, arrayed, assonant, assonantal, assorted,
   at one, attuned, blended, blending, categorized, chiming,
   classified, coexistent, coexisting, coherent, coincident,
   coinciding, commensurate, compatible, composed, concordant,
   concurring, conformable, congenial, congruent, congruous,
   consentaneous, consentient, consistent, consonant, constituted,
   cooperating, cooperative, correspondent, corresponding, disposed,
   en rapport, equivalent, fixed, graded, grouped, harmonic,
   harmonious, harmonized, harmonizing, homophonic, in accord,
   in agreement, in chorus, in concert, in concord, in phase,
   in rapport, in step, in sync, in synchronization, in tempo,
   in time, in tune, in unison, inaccordance, inharmony, like-minded,
   marshaled, methodized, monodic, monophonic, normalized, of a piece,
   of like mind, of one mind, on all fours, on the beat, ordered,
   orderly, organized, placed, positive, proportionate, ranged,
   ranked, reconcilable, regularized, regulated, routinized,
   self-consistent, sorted, standardized, symbiotic, symphonious,
   synchronal, synchronic, synchronous, systematized, tuned,
   unanimous, uniform, unisonant, unisonous