What is "black cumin"

Cumin \Cum"in\ (k?m"?n), n. [OE.comin, AS. cymen, fr. L. cuminum, Gr. ???????; of Semitic origin, cf. Ar. kamm?n, Heb. kamm?n; cf. OF. comin, F. cumin. Cf. Kummel.] (Bot.) A dwarf umbelliferous plant, somewhat resembling fennel ( Cuminum Cyminum), cultivated for its seeds, which have a bitterish, warm taste, with an aromatic flavor, and are used like those of anise and caraway. [Written also cummin.]

Rank-smelling rue, and cumin good for eyes.
--Spenser.

Black cumin (Bot.), a plant ( Nigella sativa) with pungent seeds, used by the Afghans, etc.

Black cumin can refer to the seeds of either of two quite different plants, both of which are used as spices:

• Bunium bulbocastanum, black cumin is considered similar to caraway, but they are two distinctly different plants. The seeds differ dramatically in shape, color and size.
• Nigella sativa, black caraway is also called kalonji or nigella, and more common in the Far East, Mideast, India and Africa.