Definition of "indigo" []

• 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. (noun)
• A blue dye obtained from these plants or produced synthetically. (noun)
• Any of several related plants, especially those of the genera Amorpha or Baptisia. (noun)
• 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. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "I never heard the term indigo child until I read this article, but there it was in the New York Times on Thursday, and then last night at the video store I saw this--clearly some kind of confluence, at least for me."
• "He told the reporter he hates labels..doesnt like the term indigo and felt the parents need the help not the kids."
• "Newton said it had 7, so most say 7, but many people drop indigo from the list, since humans are generally very poor at differentiating indigo from blue/violet."