Oregano is a herb that is found in both Mediterranean and Mexican cuisine. The leaves are used either fresh or dried, but the taste is stronger in the dried herb. The Mediterranean variety is mild in flavor, whereas its Mexican counterpart has a more earthly taste. It can be used with anything that has tomato and in salads, and is frequently used in pizza toppings and guacamole.
Oregano is very similar to marjoram, another herb from the same family, and is sometimes called wild marjoram or pot marjoram. Oregano is stronger in flavor than marjoram, and marjoram is sweeter.