Indigo

About

"n. A substance obtained in the form of a blue powder from leguminous plants of the genus Indigofera, and used as a blue dye. See indigoplant.

n. The violet-blue color of the spectrum, extending, according to Helmholtz, from G two thirds of the way to F in the prismatic spectrum. The name was introduced by Newton, but has lately been discarded by the best writers.

n. An American leguminous plant, Baptisia australis. See Baptisia. Also called blue false indigo and wild indigo.

n. Same as Japanese indigo.

n. In Australia, any plant of the genus Swainsona of the bean family, especially S. galegifolia. See Swainsona."

-- from The Century Dictionary and Cyclopedia

Nota bene: I might have left some things over on the woad list, too.