countable/uncountable a situation in which separate things happen by chance at the same time or in the same waycoincidence that: It was rather a coincidence that she appeared at that exact moment.
by coincidence: By coincidence, his teaching contract finished at about the same time his first book was published.
no coincidence: It is no coincidence that coastal communities have often been deeply religious.
pure/sheer coincidence: It might have been planned or it might have been pure coincidence.