Ajwain or Ajowan Caraway (botanical name of Trachyspermum copticum as from the ITIS Standard Report Page) (also known as Ajowan caraway, carom seeds or mistakenly as bishop's weed), is an uncommon spice except in certain areas of Asia. It is the small seed-like fruit 'similar to that' of the Bishop's Weed(Ammi majus) plant, egg-shaped and grayish in colour. The plant has a similarity to parsley. Because of their seed-like appearance, the fruit pods are sometimes called ajwain seeds or mistakenly as bishop's weed (Ammi majus) seeds (Botanical Synonyms for Ajwain, which are no longer accepted by ITIS are, Ammi copticum, Carum copticum, Trachyspermum ammi).
Ajwain is often confused with lovage seed; even some dictionaries mistakenly state that ajwain comes from the lovage plant. Ajwain is also called 'owa' in Marathi, 'vaamu' in Telugu, "omam" (ஓமம்) in Tamil, "ajwana" in Kannada, "ajmo" (અજમો) in Gujarati, "jowan" in Bengali and "asamodagam" in Singhalese.
Raw ajwain smells almost exactly like thyme because it also contains thymol, but is more aromatic and less subtle in taste, as well as slightly bitter and pungent. It tastes like thyme or caraway, only stronger. Even a small amount of raw ajwain will completely dominate the flavor of a dish.
In Indian cuisine, ajwain is almost never used raw, but either dry-roasted or fried in ghee or oil. This develops a much more subtle and complex aroma, somewhat similar to caraway but "brighter". Among other things, it is used for making a type of paratha, called 'ajwain ka paratha'.
Ajwain originated in the Middle East, possibly in Egypt. It is now primarily grown and used in the Indian Subcontinent, but also in Iran, Egypt and Afghanistan. It is sometimes used as an ingredient in berbere, a spice mixture favored in Eritrea and Ethiopia.