WordWeb Online

1. Occurring or existing at the same time or having the same period or phase
   "a synchronous set of clocks"; "the synchronous action of a bird's wings in flight"; "synchronous oscillations"; "recovery was synchronous with therapy";
   - synchronal, synchronic
    
2. (digital communication) pertaining to a transmission technique that requires a common clock signal (a timing reference) between the communicating devices in order to coordinate their transmissions

See also: coetaneous, coeval, coexistent, coexisting, coincident, coincidental, coinciding, concurrent, contemporaneous, contemporary, co-occurrent, cooccurring, parallel, simultaneous, synchronic, synchronised [Brit], synchronized

Antonym: asynchronous

Encyclopedia: Synchronous