Definition of madder
1
:a Eurasian herb (Rubia tinctorum of the family Rubiaceae, the madder family) with whorled leaves and small yellowish panicled flowers succeeded by dark 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
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