- a European plant, Isatis tinctoria, of the mustard family, formerly cultivated for a blue dye extracted from its leaves.
- the dye extracted from this plant.
- a European plant, Isatis tinctoria, formerly cultivated for its leaves, which yield a blue dye: family Brassicaceae (crucifers)
- the dye obtained from this plant, used esp by the ancient Britons, as a body dye
