Finnish: Jumala or Estonian: Jumal or Mari: Jumo  means "god" in the Finnic languages and those of the Volga Finns (Mari, Erzya and Moksha languages), both the Christian god and any other deity of any religion. The word is thought to have been the name of a sky god of the ancient Finnic-speaking peoples. Jumala as a god of the sky is associated with the related Estonian Jumal, Mari Jumo and Bjarmian Jomali and is thought to stem from an ancient tradition of the Finno-Ugric peoples. A related term appears also in the Mordvinic languages, jondol "lightning", literally "fire of Juma" (cf. tol "fire").
The terms are usually considered to derive from a common Finno-Permic root *juma. No equivalents are found in the Ugric languages, and there are different theories concerning the earlier origin of the word. One possible origin is Baltic languages (cf. Jumis — Latvian god of fertility, one of the divine twins). An Indo-Iranian origin for the name has been proposed, comparing e.g. Sanskrit dyumān "heavenly", "shining", but this remains disputed.
This name replaced the original Finno-Ugric word for "heaven" (*ilma), which is preserved in the Sámi and Permic languages but whose meaning was shifted to "air" in Finnic. The older sense remains in the Finnish divine name Ilmarinen.
In Estonia, Jumal was the name of the god of the sky. He was believed to make the earth fertile through the rains of the summer's thunderstorms. Among the south Estonians, he was represented by a wooden statue in their homes.
According to John Martin Crawford in the preface to his translation of the Kalevala:
The Finnish deities, like the ancient gods of Italy, Greece, Egypt, Vedic India or any ancient cosmogony, are generally represented in pairs, and all the gods are probably wedded. They have their individual abodes and are surrounded by their respective families. ... The heavens themselves were thought divine. Then a personal deity of the heavens, coupled with the name of his abode, was the next conception; finally this sky-god was chosen to represent the supreme Ruler. To the sky, the sky-god, and the supreme God, the term Jumala (thunder-home) was given.
Later on, the sky itself was called taivas and the sky-god Ukko Ylijumala, literally Grandfather or Old Man Overgod.  However, when Christianity came to dominate Finnish religious life in the Middle Ages and the old gods were ousted or consolidated away from the pantheon, Jumala became the Finnish name for the Christian God.
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