dill, Old World annual or biennial plant (Anethum graveolens) of the family Umbelliferae (parsley family), cultivated since at least since 400 B.C. The pungent, aromatic leaves and seeds are used for pickling and for flavoring sauces, salads, and soups. Dill water (a carminative) and oil of dill are made from the seeds. Dill was formerly used in charms against witchcraft. Dill is classified in the division Magnoliophyta, class Magnoliopsida, order Apiales, family Umbelliferae.