Dill seed is the dried seed of the dill plant (Anethum graveolens), used whole or ground as a spice. It tastes noticeably different from the plant's leaves (dill weed): where the leaves are grassy and mild, the seeds are more concentrated and aromatic, with notes of anise, caraway, and citrus.
Dill seed has been used since antiquity, with evidence of cultivation in ancient Egypt and references in Greek and Roman texts. It's a defining flavor in Scandinavian and Eastern European dishes like gravlax, pickles, and borscht, and also appears in Indian chutneys, Middle Eastern spice blends, and German sausages. In pickling, it's typically combined with garlic, peppercorns, and vinegar; it also pairs well with yogurt, sour cream, poultry, and legumes.