Source : Webster's Revised Unabridged Dictionary (1913)

Alexanders \Al`ex*an"ders\, Alisanders \Al`i*san"ders\, n. [OE.
   alisaundre, OF. alissandere, fr. Alexander or Alexandria.]
   (Bot)
   A name given to two species of the genus {Smyrnium}, formerly
   cultivated and used as celery now is; -- called also {horse
   parsely}.

Source : WordNet®

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