When the term coincidence was first mentioned in a 1626 natural history book by Francis Bacon, it described the situation where two things were in the same location. Over time, it also came to mean “occurring at the same time”, and by the 1680s, the definition of “remarkable concurrence” was added. The word originates from the Latin verb coincidere, which is a combination of the prefix cum- (meaning “with”), the prefix in- (meaning “into”), and the verb cadere (meaning “to fall”). In essence, a coincidence was an event where things fell into alignment. The root word cadere, which also gives rise to words like cascade, decadence, cadaver, and decay, can be traced back to the Proto-Indo-European reconstruction khd, also signifying “to fall.”
