mad·der / ˈmadər/ • n. a scrambling or prostrate Eurasian plant (genera Rubia and Sherardia) of the bedstraw family, with whorls of four to six leaves, in particular R. tinctorum of southern Europe and western Asia, formerly cultivated for its root, which yields a red dye. ∎  a red dye or pigment obtained from the root of this plant, or a synthetic dye resembling it.

madder herbaceous climbing plant cultivated for a dye-stuff; formerly in wider use. OE. mædere, corr. to OHG. matara, ON. maðra, rel. to MLG., MDu. mēde; of uncert. orig.