coincidence, happenstance -- (an event that might have been arranged although it was really accidental)
coincidence -- (the quality of occupying the same position or area in space; "he waited for the coincidence of the target and the cross hairs")
concurrence, coincidence, conjunction, co-occurrence -- (the temporal property of two things happening at the same time; "the interval determining the coincidence gate is adjustable")
(Sound)
