[1] : The Collaborative International Dictionary of English v.0.48

zend-avesta \zend`-aves"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.
   1913 webster

[2] : WordNet (r) 2.0

zend-avesta
     n : a collection of zoroastrian texts gathered during the 4th or
         6th centuries syn: avesta
see also:
avesta 

Zend-Avesta >> Z Words
Zend-Avesta, definition of term: Zend-Avesta
zend-avesta_pag1.html