The Collaborative International Dictionary of English v.0.48:

Veadar \Ve"a*dar\, n.
   The thirteenth, or intercalary, month of the Jewish
   ecclesiastical calendar, which is added about every third
   year.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Veadar
    n 1: included seven times in every 19 years [syn: Veadar,
         Adar Sheni]