[adj] occurring or existing at the same time or having the same period or phase; "recovery was synchronous with therapy"- Jour.A.M.A.; "a synchronous set of clocks"; "the synchronous action of a bird's wings in flight"; "synchronous oscillations"
at the same time(p), coetaneous, coeval, coexistent, coexisting, coincident, coincidental, coinciding, concurrent, contemporaneous, contemporary, cooccurring, in parallel(p), parallel, simultaneous, synchronic, synchronised, synchronized, synchronous
asynchronous