noun
A purplish-blue color.
An indigo-colored dye obtained from certain plants (indigo plant or woad), or a similar synthetic dye.
An indigo plant, such as from species in genera Indigofera, Amorpha (false indigo), Baptisia (wild indigo), and Psorothamnus and Dalea (indigo bush).
adjective
having a deep purplish-blue colour