Source : Webster's Revised Unabridged Dictionary (1913)

Olusatrum \O*lu"sa*trum\, n. [L. holusatrum, olusatrum; olus
   garden herb + ater black.] (Bot.)
   An umbelliferous plant, the common Alexanders of Western
   Europe ({Smyrnium Olusatrum}).

Source : WordNet®

Smyrnium olusatrum
     n : European herb somewhat resembling celery widely naturalized
         in Britain coastal regions and often cultivated as a
         potherb [syn: {Alexander}, {Alexanders}, {black lovage},
         {horse parsley}]