Thunderer - Thunder

The most terrifying sight for any grain farmer anywhere. Angry thunder god about to destroy everything they worked for all year. I talked about this in my post "The power of thunder giant". 

In the past people were convinced that the sky was the domain of the sky father, sky (thunder) god. It was him who caused thunder and lightning. And so when people heard thunder and saw lightning, they would point to the sky and say with fear: "the sky (thunder) god such and such"...

This is why in some Slavic and Baltic languages the word for thunderbolt and for thunder god is the same: Perun. This was originally just the God's name, which people exclaimed in fear during thunderstorms, and only later, after Christianisation this became "only" a  thunderbolt.

This is the depiction of the god Perun holding his axe. Left of him is the so called "Perunika" (Perun's flower, or Perun's wheel), otherwise known as "Thunder mark". Thunder marks were engraved on buildings to protect them against lightning...

We find the same situation in Celtic culture, where thunder god Taranis eventually became "just thunderbolt". Welsh "taranu, taran", Breton: "taraniñ, taran", Cornish "taran", Gaelic "tórnach" all mean "to thunder and thunder"...

This is the depiction of the god Taranis holding both the solar wheel and thunderbolt...

In Slavic mythology, Thunder god Perun's wheel is blazing Sun god Svetovid's wheel...

In Slavic mythology this dual aspect of Sky God is preserved in the character of St Elijah the Thunderer. I wrote about him in my post "Thundering sun god"...

Finnish Sky (Thunder) god was Ukko and thunder is Ukkonen. Again the Sky god became "just thunder"...

In Germanic mythology there's something similar. In most Germanic languages the name of the thunder god and the word for thunder were (almost) identical. Proto-Germanic root for thunder was *þunraz and Proto-Germanic root for the thunder god was also *Þunraz...

This is a statuette of Zeus hurling a thunderbolt from Dodona, Epirus, Greece

Now here is the question: where does South Slavic word "sev, sijev" meaning flash (chiefly referring to lightning) come from? And does it have anything to do with Zeus (Zevs in Serbian, Zefs in early mediaeval Greek)? Maybe Balkan "Slavic" population originally pronounced the God's name as Sev which became the name for the thunder and lightning after the Christianisation? 

What is very interesting is this: The god's name in the nominative was Ζεύς (Zeús). It was inflected as follows: vocative: Ζεῦ (Zeû); accusative: Δία (Día); genitive: Διός (Diós); dative: Διί (Dií). 

A vocative expression is an expression of direct address. This is what we use when we are shouting someones name. In this case when we are shouting thunder god's name. So maybe I am right? People used to look at the rumbling sky and shout Ζεῦ (Zeû) = Sev...

Interesting indeed...

BTW, the official etymology of sevati is Limited to South Slavic, formed as *sijati (“to shine, to illuminate”) +‎ *-vati, from Proto-Indo-European *(s)ḱeh₁y- (“to shine”)...