Oregano is the dried leaves of the herbs Origanum vulgare.Mediterranean Oregano, which gained its popularity after WWII, is found in much of Italian cuisine: pizza, spaghetti sauces, and other tomato-based sauces. The word "Oregano" is Greek, derived and translated means "Joy of the Mountain". Oregano was popular in ancient Egypt and Greece as a flavoring for vegetables, wines, meats and fish.