The Collaborative International Dictionary of English v.0.48:
Calumba \Ca*lum"ba\, n. [from kalumb, its native name in Mozambique.] (Med.) The root of a plant (Jateorrhiza Calumba, and probably Cocculus palmatus), indigenous in Mozambique. It has an unpleasantly bitter taste, and is used as a tonic and antiseptic. [Written also colombo, columbo, and calombo.] [1913 Webster] American calumba, the Frasera Carolinensis, also called American gentian. Its root has been used in medicine as bitter tonic in place of calumba. [1913 Webster]