The article reveals the meaning of the word "sky".
Origin, etymology
Often the word "heaven" is correlated with "heaven" and consider them very similar. The etymological dictionary of the Russian language indicates that both words came from one common Latin latin nebula (“nebula, haze, cloud”), which was formed from the pra-Indo-European nebh.
There is also a version that “heaven” and “heaven” come from the words “no demons”. Thus, this is a place where there are no demons and evil.