Wikipedia
Lithuanian Dievas, Latvian Dievs, Latgalian Dīvs, Prussian Deywis, Yotvingian Deivas was the supreme god in the Baltic mythology and one of the most important deities together with Perkūnas. Dievas is a direct successor of the Proto-Indo-European supreme god *Dyēus of the root *deiwo-. Its Proto-Baltic form was *Deivas.
In recent Lithuanian, this word may refer to the deity of any kind (Pagan, Christian, fictional and the like).
In English, Dievas may be used as a word to describe the God (or, the supreme god) in the pre-Christian religion of Balts, where Dievas was understood to be the supreme being of the world. In Lithuanian and Latvian, it is also used to describe God as it is understood by major world religions today. Earlier *Deivas simply denoted the shining sunlit dome of the sky, as in other Indo-European mythologies. The celestial aspect is still apparent in phrases such as Saule noiet dievā, from Latvian folksongs. In Hinduism any deity is known as Deva, a result of shared Proto-Indo-European roots.