'peaty' originates from English, specifically the noun 'peat', where 'peat' meant 'partially decayed vegetable matter (turf) used as fuel'; the adjective was formed by adding the suffix '-y' to mean 'having the quality of peat'.

'peat' comes from Old English (or early Middle English) forms such as 'pyt'/'pete' (Middle English 'pete'), which referred to turf or decayed vegetable matter; over time English formed the adjective 'peaty' (Modern English) by adding the adjectival suffix '-y' to 'peat'.

Initially 'peat' referred to the material (turf/decayed vegetation) itself; over time the adjective 'peaty' came to mean 'having the characteristics (smell/taste) of peat', especially applied to aromas and flavors (e.g., in whisky).