'attemper' originates from Latin, specifically the word 'adtemperare', where 'ad-' meant 'to/toward' and 'temperare' meant 'to mix, regulate, restrain'.

'attemper' changed from Old French 'attemperer' and Middle English 'attemperen' and eventually became the modern English word 'attemper'.

Initially, it meant 'to bring into proper proportion or regulate', and over time it evolved into its current meaning of 'to adjust or moderate'.