(n.) An herbaceous cruciferous plant (Isatis tinctoria). It was formerly cultivated for the blue coloring matter derived from its leaves.
(n.) 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 It is now superseded by indigo, but is somewhat used with indigo as a ferment in dyeing.
Example Sentences:
(1) N.m.r.-, magnetic-c.d.- and e.p.r.-spectroscopic studies of oxidized and reduced cytochrome f from charlock, rape and woad are reported.
(2) Well, most people outside Ukip’s woad-wearing tendency and the wilder shores of Tory little Englanderism can probably say yes to that.