'three-colored' originates from a compound of two English elements: 'three' (from Old English 'þrīe') and 'colored' (from the adjective formed from Old French 'colour', ultimately from Latin 'color'), where 'þrīe' meant 'three' and Latin 'color' meant 'a hue or appearance'.

'three' developed from Old English 'þrīe' (and related Proto-Germanic forms) into Middle English 'thre/three'; 'colour' came into English via Old French 'colour' (Latin 'color'), producing Middle English forms like 'colur' and later the adjective 'coloured/colored'; the compound 'three-coloured' (UK) / 'three-colored' (US) emerged as the descriptive phrase in Modern English.

Initially it literally meant 'having three colours'; its core meaning has remained the same over time, describing something composed of or marked by three colors.