& Telecommunications of or requiring a form of computer control timing protocol in which a specific operation begins upon receipt of an indication (signal) that the preceding operation has been completed.
2not going at the same rate and exactly together with something else, in particular. (of a machine or motor) not working in time with the alternations of current. Astronomy (of a satellite) revolving around the parent planet at a different rate from that at which the planet rotates. Astronomy (of an orbit) such that a satellite in it is asynchronous. 3(of two or more objects or events) not existing or happening at the same time.