'hippopotamus' originates from Greek, specifically the word 'hippopotamos,' where 'hippos' meant 'horse' and 'potamos' meant 'river.'

'hippopotamos' transformed into the Latin word 'hippopotamus,' and eventually became the modern English word 'hippopotamus.'

Initially, it meant 'river horse,' but over time it evolved into its current meaning of 'a large, mostly herbivorous mammal.'