'mellowness' originates from Middle English, specifically the word 'melwe', where 'melwe' meant 'soft, tender, ripe'.

'melwe' changed from Old English word 'melu' and eventually became the modern English word 'mellow', from which 'mellowness' is derived.

Initially, it meant 'softness or ripeness', but over time it evolved into its current meaning of 'smoothness, richness, or calmness in taste, sound, or mood'.