any of a genus (Rubia) of plants of the madder family, with petals fused to form a funnel-shaped corolla; esp., a perennial vine (R. tinctorum) with panicles of small, yellow flowers
the red root of this vine
a red dye made from this
bright red; crimson
adjective
designating a family (Rubiaceae, order Rubiales) of chiefly tropical, dicotyledonous herbs, shrubs, and trees, including bedstraw, bluet, coffee, and cinchona