'coincidental' originates from the Latin word 'coincidere,' where 'co-' meant 'together' and 'incidere' meant 'to fall upon.'

'coincidere' transformed into the French word 'coïncider,' and eventually became the modern English word 'coincide' through Middle English.

Initially, it meant 'to fall together,' but over time it evolved into its current meaning of 'happening at the same time by chance.'