'three-toned' originates from English, specifically the words 'three' and 'tone' combined with the adjectival suffix '-ed', where 'three' originally meant '3' (from Old English 'þrīe') and 'tone' meant 'pitch' or 'stretch' (from Greek 'tonos' via Latin 'tonus').

'three' changed from Old English 'þrīe' (from Proto-Germanic *þrīz) and 'tone' entered English via Old French 'ton' from Latin 'tonus' and Greek 'tonos'; the adjectival form with '-ed' produced compounds like 'three-toned' in Modern English.

Initially it meant something literally possessing three tonal qualities (in sound or color); over time it broadened to describe objects or sounds characterized by three distinct colors, shades, or pitches.