A coincidence is two events that happen at the same time or in close succession, or appear somehow to be related, but neither one has actually caused the other in any way.
Examples of coincidences:
a 4th grader chooses a dinosaur book at the library and his teacher begins a science unit about dinosaurs the very next day I am thinking about a friend I haven't heard...
No, everything has a purpose no matter how stupid it may seem. But the purpose doesn't have to be something big or wonderful, and it may never be known, but there is a reason for everything.