'waterfall' originates from Old English, specifically the words 'wæter' meaning 'water' and 'feallan' meaning 'to fall'.

'wæter' and 'feallan' combined to form the Middle English word 'waterfalle', which eventually became the modern English word 'waterfall'.

Initially, it meant 'a fall of water', and this meaning has largely remained the same in modern usage.