in·di·go (ĭn'dĭ-gō')
n., pl., -gos, or -goes.

1. 1. Any of various shrubs or herbs of the genus Indigofera in the pea family, having odd-pinnate leaves and usually red or purple flowers in axillary racemes.
   2. A blue dye obtained from these plants or produced synthetically.
2. Any of several related plants, especially those of the genera Amorpha or Baptisia.
3. The hue of that portion of the visible spectrum lying between blue and violet, evoked in the human observer by radiant energy with wavelengths of approximately 420 to 450 nanometers; a dark blue to grayish purple blue.

[Spanish índigo and Dutch indigo (from Portuguese endego), both from Latin indicum, from Greek Indikon (pharmakon), Indian (dye), neuter of Indikos, of India, from India, India, from Indos, the Indus River, from Old Persian Hinduš, Sind. See Hindi.]

indigo in'di·go' adj.

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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

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