{Indigo berry} (Bot.), the fruit of the West Indian shrub
{Randia aculeata}, used as a blue dye.
{Indigo bird} (Zo["o]l.), a small North American finch
({Cyanospiza cyanea}). The male is indigo blue in color.
Called also {indigo bunting}.
{Indigo blue}.
(a) The essential coloring material of commercial indigo,
from which it is obtained as a dark blue earthy powder,
with a reddish luster, {C16H10N2O2}, which may be
crystallized by sublimation. Indigo blue is also made
from artificial amido cinnamic acid, and from artificial
isatine; and these methods are of great commercial
importance. Called also {indigotin}.
(b) A dark, dull blue color like the indigo of commerce.
{Indigo brown} (Chem.), a brown resinous substance found in
crude indigo.
{Indigo copper} (Min.), covellite.
{Indigo green}, a green obtained from indigo.
{Indigo plant} (Bot.), a leguminous plant of several species
(genus {Indigofera}), from which indigo is prepared. The
different varieties are natives of Asia, Africa, and
America. Several species are cultivated, of which the most
important are the {I. tinctoria}, or common indigo plant,
the {I. Anil}, a larger species, and the {I. disperma}.
{Indigo purple}, a purple obtained from indigo.
{Indigo red}, a dyestuff, isomeric with indigo blue, obtained
from crude indigo as a dark brown amorphous powder.
{Indigo snake} (Zo["o]l.), the gopher snake.
{Indigo white}, a white crystalline powder obtained by
reduction from indigo blue, and by oxidation easily
changed back to it; -- called also {indigogen}.
{Indigo yellow}, a substance obtained from indigo.
2. (Physiol. Chem.) Same as {Indican}, 2.