What is the meaning of Madder?

A herbaceous plant, Rubia tinctorum, native to Asia, cultivated for a red-purple dye (alizarin) obtained from the root.

The root of the plant, used as a medicine or a dye.

A dye made from the plant.

A deep reddish colour, like that of the dye.

Of a deep reddish purple colour, like that of the dye.

To dye with madder.

comparative form of mad: more mad

Obsolete form of mether.

Eye dialect spelling of matter.

comparative degree of mad

Source: wiktionary.org