origanumPronunciation: /ɒˈrɪg(ə)nəm/Definition of origanum noun an aromatic plant of a genus that includes marjoram and oregano. Genus Origanum, family Labiatae Origin:Latin, from Greek origanon, perhaps from oros 'mountain' + ganos 'brightness'origanum in other Oxford dictionaries Definition of origanum in the US English dictionary