Dill (Anethum graveolens) is an annual herb in the celery family Apiaceae. It is the only species in the genus Anethum. Dill is grown widely in Eurasia where its leaves and seeds are used as a herb or spice for flavouring food.

Dill grows up to 40–60 cm (16–24 in), with slender hollow stems and alternate, finely divided, softly delicate leaves 10–20 cm (4–8 in) long. The ultimate leaf divisions are 1–2 mm (0.04–0.08 in) broad, slightly broader than the similar leaves of fennel, which are threadlike, less than 1 mm (0.04 in) broad, but harder in texture.

Fresh and dried dill leaves (sometimes called "dill weed" to distinguish it from dill seed) are widely used as herbs in Europe and central Asia.

Like caraway, the fern-like leaves of dill are aromatic and are used to flavor many foods such as cured salmon, and other fish dishes, borscht, and other soups, as well as pickles.

Dill is best when used fresh, as it loses its flavor rapidly if dried, however, freeze-dried dill leaves retain their flavor relatively well for a few months.

Dill oil is extracted from the leaves, stems, and seeds of the plant. The oil from the seeds is distilled and used in the manufacturing of soaps.

More Info: en.wikipedia.org