'affusion' originates from Latin, specifically the word 'affusio,' where 'ad-' meant 'toward' and 'fundere' meant 'to pour.'

'affusio' transformed into the French word 'affusion,' and eventually became the modern English word 'affusion' through Middle English.

Initially, it meant 'to pour upon,' but over time it evolved into its current meaning of 'the act of pouring a liquid, especially as a religious rite or medical treatment.'