The Collaborative International Dictionary of English v.0.48:

Alexander \Alexander\ n.
   1. 1 a European herb (Smyrnium olusatrum) somewhat
      resembling celery widely naturalized in Britain coastal
      regions and often cultivated as a potherb.

   Syn: Alexanders, black lovage, horse parsley
        [WordNet 1.5]

   2. 1 the famous king of Macedon, son of Philip; conqueror of
      Greece and Egypt and Persia; founder of Alexandria --
      (356-323 BC).

   Syn: Alexander the Great
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Alexander
    n 1: European herb somewhat resembling celery widely naturalized
         in Britain coastal regions and often cultivated as a
         potherb [syn: Alexander, Alexanders, black lovage,
         horse parsley, Smyrnium olusatrum]
    2: king of Macedon; conqueror of Greece and Egypt and Persia;
       founder of Alexandria (356-323 BC) [syn: Alexander,
       Alexander the Great]