'fortnight' originates from Old English, specifically the word 'fēowertīene niht,' where 'fēowertīene' meant 'fourteen' and 'niht' meant 'nights.'

'fēowertīene niht' transformed into the Middle English word 'fourtenight,' and eventually became the modern English word 'fortnight.'

Initially, it meant 'fourteen nights,' but over time it evolved into its current meaning of 'a period of two weeks.'