'estimation' originates from Latin, specifically the word 'aestimatio,' where 'aestimare' meant 'to value or appraise.'

'aestimatio' transformed into the Old French word 'estimacion,' and eventually became the modern English word 'estimation' through Middle English.

Initially, it meant 'to value or appraise,' but over time it evolved into its current meaning of 'a rough calculation or judgment.'