The Collaborative International Dictionary of English v.0.48:

Iyar \Iyar\, Iyyar \Iyyar\n.
   The eighth month of the civil year in the Jewish calendar;
   the second month of the ecclesiastical year (in April and
   May).

   Syn: Iyyar.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Iyar
    n 1: the eighth month of the civil year; the second month of the
         ecclesiastical year (in April and May) [syn: Iyar,
         Iyyar]