Where does “молниеносно” come from?
молниеносно (Russian) comes from Russian молниено́сный, from Russian мо́лния, from Old East Slavic мълниꙗ, from Proto-Slavic mъlnьji, from Proto-Slavic mъldnьji.
молниеносно (Russian): with lightning speed
Ancestry of “молниеносно”, step by step