Where does “восточнославянский” come from?
восточнославянский (Russian) comes from Russian славя́нский, from Proto-Slavic slověnьskъ, from Proto-Slavic slověninъ, from Proto-Slavic slovo, from Proto-Balto-Slavic ślawas, from Proto-Indo-European ḱléwos, from Proto-Indo-European ḱlew-, from Proto-Indo-European ḱel- — to cover; to incline.
Ancestry of “восточнославянский”, step by step
Words derived from “восточнославянский”