woad

n. [ OE. wod, AS. wād; akin to D. weede, G. waid, OHG. weit, Dan. vaid, veid, Sw. veide, L. vitrum. ] [ Written also wad, and wade. ] [ 1913 Webster ]

1. (Bot.) 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 ]

2. 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 It is now superseded by indigo, but is somewhat used with indigo as a ferment in dyeing.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 ]

Their bodies . . . painted with woad in sundry figures. Milton. [ 1913 Webster ]

Wild woad (Bot.), the weld (Reseda luteola). See Weld. --
Woad mill, a mill grinding and preparing woad. [ 1913 Webster ]