The Collaborative International Dictionary of English v.0.48:

Origan \Or"i*gan\, Origanum \O*rig"a*num\, prop. n. [L.
   origanum, Gr. ?, ?, prob. fr. 'o`ros, mountain + ?
   brightness, beauty. Cf. Organy.] (Bot.)
   A genus of aromatic labiate plants, including the sweet
   marjoram (Origanum Marjorana) and the wild marjoram
   (Origanum vulgare). --Spenser.
   [1913 Webster]

WordNet (r) 3.0 (2006):

origanum
    n 1: any of various fragrant aromatic herbs of the genus
         Origanum used as seasonings