word-forming element meaning "of or pertaining to India" (and some other place), from Greek Indo-, from Indos "India" (see India).
Iranian adj.
1788, "of or pertaining to (ancient) Persia," from Iran + -ian. From 1839 in reference to the language. As a noun, "an inhabitant of Persia" (1792), later "the language of Persia" (1850). Iranic (adj.) is from 1847.