Heavenly end for many a Russian (3)
I believe the answer is:
sky
'russian' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for sky that I've seen before include "Orbiting space-station" , "Hit upwards" , "-- Blue" , "Hit high into the air" , "Firmament" .)