supreme god of the ancient Greeks and master of the others, 1706, from Greek, from PIE *dewos- "god" (source also of Latin deus "god," Old Persian daiva- "demon, evil god," Old Church Slavonic deivai, Sanskrit deva-), from root *dyeu- "to shine," in derivatives "sky, heaven, god." The god-sense is originally "shining," but "whether as originally sun-god or as lightener" is not now clear.