indigo comes from Spanish indico and Portuguese endego, from Latin indicum ('indigo dye'), from Ancient Greek indikon ('Indian dye'), from Indikos ('of India'), the dye's place of origin. The path is chiefly one of transmission: the word passes through the named languages and forms, with each stage preserving part of the modern shape. In present English, the noun sense is "a deep blue-violet colour or the dye that produces it", so the historical development ends in a clearly identifiable modern dictionary use. The same base also appears in related forms such as indigotin and indican. Its semantic neighborhood includes blue, violet, blue-violet, and navy, which helps locate the modern sense without adding a separate etymological claim. The named historical forms include Latin indicum and Ancient Greek indikon.