'reaffirm' originates from Latin, specifically the word 'reaffirmare,' where 're-' meant 'again' and 'affirmare' meant 'to make firm.'

'reaffirmare' transformed into the French word 'réaffirmer,' and eventually became the modern English word 'reaffirm' through Middle English.

Initially, it meant 'to make firm again,' and this meaning has largely remained the same in modern usage.