'waterer' originates from the Old English word 'wæter,' where 'wæter' meant 'water.'

'wæter' transformed into the Middle English word 'water,' and eventually became the modern English word 'waterer' by adding the suffix '-er' to denote a person or device that performs the action of watering.

Initially, it meant 'to provide water,' and this meaning has largely remained the same in modern usage.