'affiliate' originates from Medieval Latin, specifically the word 'affiliatus', where 'ad-' meant 'to' and 'filius' meant 'son'.

'affiliatus' transformed into the French word 'affilier', and eventually became the modern English word 'affiliate' through Middle English.

Initially, it meant 'to adopt as a son', but over time it evolved into its current meaning of 'to associate or connect with an organization'.