'bi-coloured' originates from Latin and Old French, specifically the Latin prefix 'bi-' (from Latin 'bis') meaning 'twice' and Old French/Latin 'colour' (Old French 'colour', from Latin 'color') meaning 'hue, appearance'.

'bi-coloured' developed in English by combining the prefix 'bi-' (Latin 'bis') with the Middle English/Old French word for 'colour' (Old French 'colour', Middle English 'colour'), eventually forming the Modern English adjective 'bi-coloured' (also attested as 'bicolour'/'bicolored').

Initially, the components meant 'twice' and 'hue/colour'; combined they have long meant 'having two colours', a meaning that has remained stable into modern usage.