[AS. maeddere.] The name of a very useful red dye obtained from the roots of the madder plant, which is found in the warm parts of the Old and New Worlds. Madder is used by dyers to make a great variety of red tints, and by varying the mordant such colors as madder-orange, madder-purple, madder-yellow, etc., are easily produced. Turkey-red used in dyeing cotton goods is a madder color. Alizarin, the red coloring principle of madder, is now made artificially.