[ 'ɪndɪgəʊ ]
■ noun ( plural ~s or ~es )
1》 a tropical plant formerly widely cultivated as a source of dark blue dye. [ Indigofera tinctoria and related species.]
2》 the dark blue dye obtained from the ~ plant.
↘a colour between blue and violet in the spectrum.
Origin
C16: from Port. índigo , via L. from Gk indikon , from indikos 'Indian (dye)'.