WordNet (r) 3.0 (2006):

sync
    v 1: make synchronous and adjust in time or manner; "Let's
         synchronize our efforts" [syn: synchronize,
         synchronise, sync] [ant: desynchronise,
         desynchronize]

Moby Thesaurus II by Grady Ward, 1.0:

75 Moby Thesaurus words for "sync":
   accommodate, accord, accordance, adapt, adjust, adjust to,
   affinity, agreement, assent, assimilate, attune, chorus, coherence,
   coincidence, compatibility, concert, concord, concordance,
   conformance, conformation, conformity, congeniality, congruence,
   congruency, congruity, consistency, consonance, consort,
   cooperation, coordinate, correspondence, cut to, equalize,
   equivalence, fit, fix, gear to, harmonize, harmony, homologate,
   homologize, intersection, key to, make plumb, make uniform,
   measure, oneness, overlap, parallelism, peace, proportion,
   put in tune, rapport, reconcile, rectify, regulate, right,
   self-consistency, set, set right, similarize, symmetry,
   synchronism, synchronize, tailor, tally, timing, trim to, true,
   true up, tune, uniformity, union, unison, unisonance



The Jargon File (version 4.4.7, 29 Dec 2003):

sync
 /sink/, vi.

    (var.: synch)

    1. To synchronize, to bring into synchronization.

    2. [techspeak] To force all pending I/O to the disk; see flush, sense 2.

    3. More generally, to force a number of competing processes or agents to a
    state that would be ?safe? if the system were to crash; thus, to checkpoint
    (in the database-theory sense).


The Free On-line Dictionary of Computing (30 December 2018):

sync

   /sink/ (Or "synch") 1. To synchronise, to bring into
   synchronisation.

   2.  To force ("flush") all pending buffered
   disk writes to the disk.

   3. More generally, to force a number of competing processes or
   agents to a state that would be "safe" if the system were to
   crash, i.e. to checkpoint in the database sense.

   [Jargon File]

   (1994-11-11)