What is Woad?

1. a perennial herb (Isatis tinctoria) of the mustard family, formerly grown as a source of blue dye, now sometimes cultivated for its clusters of small four-petaled yellow flowers.
2. a blue dye-stuff prepared from the leaves of Isatis tinctoria, powdered and fermented, now generally superseded by indigo. Woad was commonly used as body paint by the ancient Britons.
3. a Celtic harp duo consisting of Deborah Bennett and Maggie Pinckard!