(1) The dried and powdered root of Rubia tinctorum (family Rubiaceae); it contains several glycosides that produce the red dyes alizarin and purpurin on fermentation. When madder (or alizarin) is fed to young animals, the calcium in newly deposited bone salt, hydroxyapatite, is stained red. (2) Any dye obtained from plants of the madder family (Rubiaceae). SYN: Turkey red. [A.S. maedere]
