madder root
Refers to the root of the madder plant (Rubia tinctorum or related species), used historically as a source of red dye.
Madder root has been used as a dye since ancient times.
Compound of 茜 (akane, 'madder') + の (no, possessive particle) + 根 (ne, 'root'). The word is transparently derived from its components.