Perkwunos

The name of an Indo-European god of thunder or the oak may be reconstructed as *perk^wunos or *perkunos.

Another name for the thunder god contains an onomatopoeic root *tar-, continued in Gaulish Taranis and Hittite Tarhunt.

From IE *perk^ṷu- "oak-tree":

Perkūnas' wife was named Perkūnija/Perkūnė/Perperuna/Przeginia. Germanic *Þunraz (Þórr) is from a stem *(s)tene- "thunder", but the name *perk^wunos is continued in Fjörgyn, mother of Þórr.

*perk^(w)unos is reconstructed on the basis of Perkūnas. Parjanya is no exact cognate, see below.

The labiovelar is reconstructed due to a Centum word for "oak", "coniferous tree", or "mountain", "coniferous mountain forest", *perk^wus. Here also, the labiovelar is non-trivial, and indeed singular in the sequence *-k^wu-, its justification being in Latin quercus "oak", the result of an assimilatory Italo-Celtic sound law changing *p...k^w to *k^w...k^w (compare quinque, Irish cóic vs. Sanskrit pañca "five"; coquo vs. Sanskrit pacati "to cook"). Celtic *Ercunia, if cognate, did not partake in the assimilation, advising towards a cautious reconstruction of *perk^(w)us.

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