[mad.der] n [ME, fr. OE maedere; akin to OHG matara madder] (bef. 12c) 1: a Eurasian herb (Rubia tinctorum of the family Rubiaceae, the madder family) with whorled leaves and small yellowish panicled flowers succeeded by berries; broadly: any of several related herbs (genus Rubia)
2. a: the root of the Eurasian madder used formerly in dyeing; also: an alizarin dye prepared from it b: a moderate to strong red