'indigo-colored' originates from English, specifically formed from the adjective 'indigo' and the adjectival suffix '-colored', where 'indigo' referred to a deep blue dye and '-colored' meant 'having the color of'.

'indigo' came into English via Latin 'indicum' and Greek 'indikón' (meaning 'of India'), and is ultimately associated with Sanskrit 'nīla' (dark blue). The compound 'indigo-colored' developed in Modern English by combining 'indigo' with '-colored'.

Initially, 'indigo' referred to the dye (and by extension 'from India'); over time it came to denote the specific deep bluish-violet color, and 'indigo-colored' now means 'having that color'.