Just recently during a dinner party discussing the ingredients of a drink originating from Majorca, there were quite a few dinner guests who thought that dill was the leafy parts of fennel and aniseed some thought was the seed of fennel.
Looking up the word for dill in French in Harrap's Dictionary I realised that part of the confusion came from dill being translated as Aneth but also as Fenouil (normally the French name for fennel). This is a good example of why it is necessarily to refer to plants by their Latin or botanical name rather then the colloquial name, to avoid confusion.
The following is a clarification of the differences and the different usage of the herbs :
Dill (Anethum graveolens) – Dill is found in Mediterranean regions and western Asia. Dill resembles fennel, but is shorter, with a single, easily uprooted hollow stem, grey-green leaves. Its leaves have a strong parsley-caraway smell.
A pungent, cooling, aromatic herb that calms and tones the digestive system, controls infection, and has a diuretic effect.
Both seeds and leaves are used in cooking, especially in Scandinavian cuisine, with eggs, fish, seafood and potatoes.
Fennel (Foeniculum vulgare) – Fennel is found in Mediterranean Europe and Asia, on wasteland and in dry, sunny places.
It is a sweet, aromatic, diuretic herb that relieves digestive problems, increases milk flow, relaxes spasms and reduces inflammation. To chew on a few seed makes your breath smell fresh and helps the digestion.
Fennel leaves and seeds are often used in fish and other local Mediterranean dishes.
Aniseed (Pimpinella anisum) – was first cultivated as a spice by the ancient Egyptians and later by the Greeks, Romans and Arabs.
The herb improves digestion, benefits the liver and circulation and has expectorant and oestrogenic effects.
It is mostly the seeds that are used to flavour confectionery and popular aniseed flavoured drinks like Pernod, Pastis, Ouzo, Raki and Arak. So maybe a glass of Pastis a day, keeps the doctor away ?
Bibliography : RHS Herbal Encyclopedia