madder UK /ˈmæd.ə(ɹ)/US /ˈmæd.ɚ/noun 4adjective 1verb 1forms 3 noun4 •A herbaceous plant, Rubia tinctorum, native to Asia, cultivated for a red-purple dye (alizarin) obtained from the root. •A dye made from the plant.Their armour was stained with madder, in such wise that they seemed bathed in blood. — 1922 •A deep reddish colour, like that of the dye.Her big head has coloured to a dim and dreadful madder. — 1946 •The root of the plant, used as a medicine or a dye. adjective1 •Of a deep reddish purple colour, like that of the dye. verb1 •(rare) To dye with madder. formsmaddered · maddering · madders