I. əˈvestən adjective
Usage: usually capitalized
Etymology: Avesta, sacred books of the ancient Zoroastrian religion (from Middle Persian Avastāk ) + English -an
: of or relating to the Avesta or to Avestan
II. noun
or aves·tic -tik
Usage: capitalized
Etymology: Avesta + English -an or -ic
: one of the two ancient languages comprising Old Iranian and that in which the sacred books of the Zoroastrian religion were written — compare : old persian