'overflow' originates from Old English, specifically the word 'oferflōwan', where 'ofer-' meant 'over' and 'flōwan' meant 'to flow'.

'oferflōwan' transformed into the Middle English word 'overflowen', and eventually became the modern English word 'overflow'.

Initially, it meant 'to flow over the brim', and this meaning has largely remained the same in modern usage.