1.NounOf objects, the property of being coincident; occurring at the same time or place.
2.NounOf events, the appearance of a meaningful connection when there is none.
"That the two writers were born and died on the same day is just a coincidence, although there are many conspiracy theories about it.; It is sheer coincidence that the cartoon resembles the local politician."
3.NounA coincidence point.
4.NounA fixed point of a correspondence; a point of a variety corresponding to itself under a correspondence.