1) Coetaneous 2) Coeval 3) Coexistent 4) Coexisting 5) Coincident 6) Coincidental 7) Coinciding 8) Concurrent 9) Contemporaneous 10) Contemporary 11) Cooccurring 12) Descriptive 13) Parallel 14) Simultaneous 15) Synchronic 16) Synchronised 17) Synchronized 18) Synchronous 
• (a.) Happening at, or belonging to, the same time; synchronous; simultaneous. • (n.) A synchronal thing or event.
Syn'chro·nal adjective [ See Synchronous .] Happening at, or belonging to, the same time; synchronous; simultaneous. Dr. H. More. 
synchronal Occurring at the same time or rate, synchronous.
synchronous.