'overran' originates from Old English, specifically the word 'oferrinnan', where 'ofer-' meant 'over' and 'rinnan' meant 'to run'.

'oferrinnan' transformed into the Middle English word 'overrennen', and eventually became the modern English word 'overrun'.

Initially, it meant 'to run over or across', but over time it evolved into its current meaning of 'to spread over or occupy'.