Mad″der (măd″dẽr), n. [OE. mader, AS. mædere; akin to Icel. maðra.] (Bot.) A plant of the genus Rubia (R. tinctorum). The root is much used in dyeing red, and formerly was used in medicine. It is cultivated in France and Holland. See Rubiaceous.
☞ Madder is sometimes used in forming pigments, as lakes, etc., which receive their names from their colors; as. madder yellow.
Field madder, an annual European weed (Sherardia arvensis) resembling madder. — Indian madder, the East Indian Rubia cordifolia, used in the East for dyeing; — called also munjeet. — Wild madder, Rubia peregrina of Europe; also the Galium Mollugo, a kind of bedstraw.