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 It is now superseded by indigo, but is somewhat used with indigo as a ferment in dyeing.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

a. Colored or stained with woad. “Man tattoed or woaded, winter-clad in skins.” Tennyson. [ 1913 Webster ]

n. [ Cf. Wood-wax. ] (Bot.) A leguminous plant (Genista tinctoria) of Europe and Russian Asia, and adventitious in America; -- called also greenwood, greenweed, dyer's greenweed, and whin, wood-wash, wood-wax, and wood-waxen. [ 1913 Webster ]