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 flavoring food.. Dill is an aromatic herb with delicate, feathery green leaves. Sometimes referred to as dill weed, dill is a member of the parsley family. Dill has been around since the Middle Ages and was thought to help defend against witchcraft. It is a well-known ingredient around the world and it's used in many European and Scandinavian dishes.