A blue dyestuff obtained from Indigofera tinctoria, and other species of Indigofera (family Leguminosae); also made synthetically. SYN: i. blue, indigotin. [L. indicum, fr. G. indikon, i., ntr. of Indikos, Indian]
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1 a) a blue dye obtained from indigo plants (as Indigofera tinctoria of Africa and India, I. anil of So. America, and I. auriculata of Arabia and Egypt)
b) the principal coloring matter C16H10N2O2 of natural indigo usu. synthesized as a blue powder with a coppery luster called also indigotin
2) INDIGO PLANT
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in·di·go (inґdĭ-go) [Gr. Indikon Indian dye] 1. any of various plants of the genus Indigofera. 2. a blue dyeing material, the aglycon of indican, found in I. tinctoria and other plants, or made synthetically. It is sometimes found in the sweat and the urine, where it is derived from urinary indican (indoxyl sulfate). 3. a color between blue and violet, produced by energy of wavelengths between 420 and 450 nm.Medical dictionary. 2011.