coincidence coincidence /koʊˈɪnsɪdəns/

noun

1. () An event that might have been arranged although it was really accidental  ( happenstance , coincidence )
   an event that might have been arranged although it was really accidental
     It was a coincidence that they ran into each other at the airport.
   It was a coincidence that they ran into each other at the airport.
   
   
2. The temporal property of two things happening at the same time  ( co-occurrence , coincidence , concurrence , conjunction )
   the temporal property of two things happening at the same time
    The interval determining the coincidence gate is adjustable
   the interval determining the coincidence gate is adjustable
   
3. The quality of occupying the same position or area in space  ( coincidence )
   the quality of occupying the same position or area in space
    He waited for the coincidence of the target and the cross hairs
   he waited for the coincidence of the target and the cross hairs