'diminish' originates from Latin, specifically the word 'diminut-', where 'de-' meant 'down' and 'minuere' meant 'to make small.'

'diminut-' transformed into the Old French word 'diminuer,' and eventually became the modern English word 'diminish' through Middle English.

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