Exact correspondence in nature, character, result, circumstances, etc.; concurrence; agreement.

an event that might have been arranged although it was really accidental

a three-tuple consisting of a time and two events

The occurrence of two or more meaningfully related events within a short span of time without any casual connection between them. See also "synchronicity".

Coincidence is the noteworthy alignment of two or more events or circumstances without obvious causal connection. The word is derived from the Latin co- ("in," "with," "together") and incidere ("to fall on").