Dill is a member of the parsley family and was originally found throughout the eastern Mediterranean and western Asia, though now it is grown all over the world, in places from California to Australia. The leaves and the seeds are edible and used as spices, flavoring everything from fish to pickles. Dill has a flavor that is a mixture between onion and caraway, but is quite unique. The flavor is most widely used in German, Russian and Scandinavian recipes, as well as being a favorite ingredient in pickling liquids.
Dill weed is the common term for the leaves of the dill plant. The plants themselves are tall with feathery leaves. The leaves can be chopped, kept whole or dried and added to any variety of dish or sauce. Fresh dill has a stronger flavor than dried, so much less is needed to flavor a dish. Dried dill has a distinct advantage for the home chef because it can be stored for several months.
Dill seeds look very much like caraway and have a strong flavor, much stronger than that of the dill leaves. They are most commonly used whole, not ground, and are often used as an accent, rather than as a main flavor, when they are included in cooking. The strong flavor makes them a preferred ingredient in pickling liquids, as it is the dill seeds that give dill pickles their name. And, as a bit of trivia, 1 tablespoon of dill seeds has as much calcium as a glass of milk, though most people are not sitting around and eating dill seeds specifically for their health.
If you have never used dill, start by adding some dried dill to equal parts sour cream and mayonnaise, with splashes of pepper and lemon juice for an easy dip. Or try one of these recipes featuring dill.