oregano a name applied in one place or another, but especially in N. America, to many of the aromatic herbs of the group treated at length under marjoram, and certain other plants. However, it is questionable whether the term oregano (or origano, as it is sometimes spelled) should be treated as a plant name. Tucker (1994) has argued persuasively that oregano is best considered as the name of a flavour. He points out that:

vast confusion exists in popular and scientific texts on the correct identity of oregano. This is partly because a multitude of plant species have been called oregano or oreganum, and often these plants are substituted for each other. Most of these plants bear a unifying chemical signature: carvacrol and, to a lesser extent, thymol.