Nigella Seeds [Nigella Sativa] are also known as Black Onion Seeds, Kalonji and sometimes Black Cumin. They are small black seeds which are bitter and peppery in flavour. They are used mostly in Indian cuisine and are an ingredient of naan bread.
True Black Cumin is a different shaped seed. It is is long and thin and looks similar to a Caraway Seed. Click here for Black Cumin.