indigo

in·di·go

noun \ˈin-di-ˌgō\

plural in·di·gos or in·di·goes

Definition of INDIGO

1

a : a blue dye obtained from indigo plants (as Indigofera tinctoria of Africa and India, I. anil of South America, and I. auriculata of Arabia and Egypt) b : the principal coloring matter C₁₆H₁₀N₂O₂ of natural indigo usually synthesized as a blue powder with a coppery luster—called also indigotin

2

: indigo plant