I. “+ adjective
Usage: usually capitalized both Is
: of, relating to, characteristic of, or constituting a subfamily of the Indo-European languages that consists of the Indic and Iranian branches
II. noun
Usage: capitalized both Is
1.
a. : the Indo-Iranian languages
b. : the unrecorded prehistoric language from which the Indo-Iranian languages are descended
2.
a. : a speaker of Indo-Iranian (sense 1b)
b. : a member of a people whose original tongue is one of the Indo-Iranian languages