Mad"der (?), n. [OE. mader, AS. maedere; akin to Icel. mara.] Bot.
A plant of the 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.
© Webster 1913.