The small, crescent-shaped seeds of a plant called Cuminum cyminum, which are used as a spice. Cumin seeds have a warm flavour and a strong, pungent aroma. There is also a smaller, darker variety of cumin called black cumin which, added to dishes whole, lends them a smoky note.
Instead of buying ground cumin, buy fresh cumin seeds, dry roast them lightly in a pan, then grind them yourself. Replace your stock frequently - like other dried spices, cumin quickly loses its pungency.
Cumin is frequently used in Indian cooking and is a regular component of curry powder and the Indian spice mixture garam masala. Cumin is also a regular in Mexican cuisine; in Europe, it flavours some cheeses and is sometimes used in baking. Add cumin seeds to dishes whole or grind them to a powder.