Read the dictionary definition of coincidence. All definitions for this word.
1. the temporal property of two things happening at the same time
1. the interval determining the coincidence gate is adjustable
2. the quality of occupying the same position or area in space
1. he waited for the coincidence of the target and the cross hairs
3. an event that might have been arranged although it was really accidental
See also:
Merriam-Webster definition of coincidence