'foment' originates from Latin, specifically the word 'fomentare,' where 'fomentum' meant 'a warm application or poultice.'

'fomentare' transformed into the Old French word 'fomenter,' and eventually became the modern English word 'foment' through Middle English.

Initially, it meant 'to apply warmth or heat,' but over time it evolved into its current meaning of 'to instigate or stir up.'