syn ‧ chro ‧ nous /ˈsɪŋkrənəs/ BrE AmE adjective formal
[ Date: 1600-1700 ; Language: Late Latin ; Origin: synchronos , from Greek , from syn- ( ⇨ ↑ syn- ) + chronos 'time' ]
if two or more things are synchronous, they happen at the same time or work at the same speed