Zeus the nominative is ("Zeús"). It is inflected as follows: vocative: (""); accusative: (); genitive: (); dative: (). Diogenes Laertius quotes Pherecydes of Syros as spelling the name, . "Zeus" is the Greek continuation of *"," the name of the Proto-Indo-European god of the daytime sky, also called *' ("Sky Father"). The god is known under this name in the Rigveda (Vedic Sanskrit "Dyaus/Dyaus Pita"), Latin (compare "Jupiter", from "Iuppiter", deriving from the Proto-Indo-European vocative *'), deriving from the root *"dyeu"- ("to shine", and in its many derivatives, "sky, heaven, god"). Zeus is the only deity in the Olympic pantheon whose
Reo (deity) inscription, part of which reads , usually interpreted as "and ("or" thereafter) a fertile(?) bull for Reue" with the epithet lost. "Reue" therefore also seems to be a dative in the Lusitanian form of the name. "Reue" appears again on the Ribeira da Venda inscription, including an epithet, as - this time the deity is receiving a sacrifice of ten sheep. K T Witczak derives the name from earlier "*diewo", suggesting that the Lusitanian language changed the Proto-Indo European "d" to "r", making Reo a sky deity similar to (and having a name cognate with) the Greek Zeus and Roman