Zend

Zand or 'Interpretation' is a term for the exegesis of Avestan texts through glosses, commentaries and translations.

As to grammatical forms, the Gâtha dialect shows not a few deviations from the current Zend language.

[The Avesta] is the only work known to be written in the Zend language.

The dialect in which these writings are composed goes usually by the name of the Zend ; it is also styled the Avestan, and sometimes the Old Bactrian, from the country Bactria, the north-easternmost region of the great Iranian territory, which is supposed to have been its specific locality.