woad (n.) Look up woad at Dictionary.com
Old English wad, from Proto-Germanic *waido- (cf. Danish vaid, Old Frisian wed, Middle Dutch wede, Dutch wede, Old High German weit, German Waid "woad"), probably cognate with Latin vitrium "glass" (see vitreous). Old type of blue dye processed from plant leaves, since superseded by indigo. French guède, Italian guado are Germanic loan-words.