The Collaborative International Dictionary of English v.0.48:

Elul \E"lul\, n. [Heb.]
   The sixth month of the Jewish year, by the sacred reckoning,
   or the twelfth, by the civil reckoning, corresponding nearly
   to the month of September.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Elul
    n 1: the twelfth month of the civil year; the sixth month of the
         ecclesiastical year in the Jewish calendar (in August and
         September) [syn: Elul, Ellul]

Easton's 1897 Bible Dictionary:

Elul
   (Neh. 6:15), the name of the sixth month of the ecclesiastical
   year, and the twelfth of the civil year. It began with the new
   moon of our August and September, and consisted of twenty-nine
   days.


Hitchcock's Bible Names Dictionary (late 1800's):

Elul, cry or outcry