Nigella sativa seed is variously called fennel flower, nutmeg flower, Roman coriander, blackseed, black caraway, or black onion seed. Other names used, sometimes misleadingly, are onion seed and black sesame, both of which are similar-looking but unrelated. The seeds are frequently referred to as black cumin (as in Bengalikalo jira), but this is also used for a different spice, Bunium persicum. The scientific name is a derivative of Latin niger “black.”
Nigella sativa has a pungent bitter taste and a faint smell of strawberries. It is used primarily in candies and liquors. The seeds have a slightly bitter flavor and resemble cumin or oregano, depending on whom you ask. They taste a bit like the bits of burned onion, poppy and sesame seeds that fall off of a toasted everything bagel.
These seeds have a whole bunch of names, some of them misleading: onion seeds, black cumin, charnushka and kalonji, to name a few. Although they resemble onion seeds or black sesame seeds, they are actually the seeds of Nigella sativa, an annual flowering plant of the Ranunculacae family.