'mastiff' originates from Old French, specifically the word 'mastin,' where 'mast-' meant 'tame' and '-in' was a diminutive suffix.

'mastin' transformed into the Middle English word 'mastif,' and eventually became the modern English word 'mastiff'.

Initially, it meant 'tame dog,' but over time it evolved into its current meaning of 'a large, powerful dog breed.'