(n) an instrument that indicates whether two periodic motions are synchronous (especially an instrument that enables a pilot to synchronize the propellers of a plane that has two or more engines), Syn. synchroniser, synchronoscope, synchronizer
The Collaborative International Dictionary of English (GCIDE) v.0.53 Collaborative International Dictionary (GCIDE)
n. [ Gr. &unr_; time + -scope. ] An instrument for measuring minute intervals of time; used in determining the velocity of projectiles, the duration of short-lived luminous phenomena, etc. [ 1913 Webster ]