Oregano is a pungent, aromatic, intense herb. Many people think oregano is an Italian spice, but it hails from many different parts of the world, including Greece and Mexico. Oregano is a member of the mint family, and is often confused with common marjoram. Identifying oregano correctly will ensure that you have robust soups, sauces and other dishes.
Inspect the leaves. Leaves of oregano are oval, slightly hairy and coarse. They should be a deep, bright-green color.
Inspect the flowers. Oregano has pink or purple flowers, while common marjoram has white flowers. Oregano tends to sprawl out as it grows, so pinching the flowers back will keep the plant compact and produce quality leaves.
Taste the leaf. Oregano will taste robust, pungent and spicy. Marjoram will taste slightly minty and have a mild citrus flavor.