An herbaceous cruciferous plant (Isatis tinctoria) of the family Cruciferae (syn. Brassicaceae). It was formerly cultivated for the blue coloring matter derived from its leaves. See isatin. [1913 Webster]
A blue dyestuff, or coloring matter, consisting of the powdered and fermented leaves of the Isatis tinctoria. It is now superseded by indigo, but is somewhat used with indigo as a ferment in dyeing. [1913 Webster]
Wild woad(Bot.), the weld (Reseda luteola). See Weld. --