'subsidiary' originates from Latin, specifically the word 'subsidiarius,' where 'sub-' meant 'under' and 'sidere' meant 'to sit.'

'subsidiarius' transformed into the French word 'subsidaire,' and eventually became the modern English word 'subsidiary' through Middle English.

Initially, it meant 'serving to assist or support,' but over time it evolved into its current meaning of 'a company controlled by another.'