Source : Webster's Revised Unabridged Dictionary (1913)

Zend-Avesta \Zend`-A*ves"ta\, n. [Properly, the Avesta, or
   sacred text, and its zend, or interpretation, in a more
   modern and intelligible language. --W. D. Whitney.]
   The sacred writings of the ancient Persian religion,
   attributed to Zoroaster, but chiefly of a later date.

Source : WordNet®

Zend-Avesta
     n : a collection of Zoroastrian texts gathered during the 4th or
         6th centuries [syn: {Avesta}]