'reimburse' originates from Latin, specifically the word 'reimbursare,' where 're-' meant 'again' and 'imbursare' meant 'to put in a purse.'

'reimbursare' transformed into the French word 'rembourser,' and eventually became the modern English word 'reimburse' through Middle English.

Initially, it meant 'to put money back into a purse,' but over time it evolved into its current meaning of 'to pay back money.'