Dyēus (also *Dyēus phter, alternatively spelled dyēws) is believed to have been chief deity in the religious traditions of the prehistoric Proto-Indo-European societies. Part of a larger pantheon, he was the god of the daylight sky, and his position may have mirrored the position of the patriarch or monarch in society. In his aspect as a father god, his consort would have been Pltwih Mhter, “Earth Mother”.
This deity is not directly attested; rather scholars have reconstructed this deity from the languages and cultures of later Indo-European peoples such as Greeks, Latins and Indo-Aryans. According to this scholarly reconstruction, Dyeus was addressed as Dyeu Phter, literally “Sky father” or “shining father”, as reflected in Latin Iūpiter, Diēspiter, possibly Dis Pater and deus pater, Greek Zeu pater (Zeus), Sanskrit Dyauṣ Pitār, and Dionysus, especially with the Thracians and Sabines.
As the pantheons of the individual mythologies related to the Proto-Indo-European religion evolved, attributes of Dyeus seem to have been redistributed to other deities. In Greek and Roman mythology, Dyeus remained the chief god, but in Vedic mythology, the etymological continuant of Dyeus became a very abstract god, and his original attributes, and his dominance over other gods, seem to have been transferred to gods such as Agni or Indra.
Rooted in the related but distinct Indo-European word *deiwos is the Latin word for deity deus. The Latin word is also continued in English divine, “deity”, and the original Germanic word remains visible in “Tuesday” (“Day of Tīwaz”) and Old Norse tívar, which may be continued in the toponym Tiveden (“Wood of the Gods”, or of Týr).
Germanic Tīwaz (known as Týr in Old Norse), Latin Deus (originally used to address Jupiter, but later adopted as the name of the Christian god), Indo-Aryan deva: Vedic/Puranic deva, Buddhist deva, Iranic daeva, daiva, diw, etc., Baltic Dievas, Celtic e.g. Gaulish Dēuos, and Slavic div(-ese) (miracle) derive from the related *deiwos. Estonian Tharapita bears similarity to Dyaus Pita in name, although it has been interpreted as being related to the god Thor.
Although some of the more iconic reflexes of Dyeus are storm deities, such as Zeus and Jupiter, this is thought to be a late development exclusive to mediterranean traditions, probably derived from syncretism with Canaanite deities and Perkwunos.
The deity’s original domain was over the daylit sky, and indeed reflexes emphasise this connection to light: Istanu (Tiyaz) is a solar deity, Helios is often referred to as the “eye of Zeus”, in Romanian paganism the Sun is similarly called “God’s eye” and in Indo-Iranian tradition Surya/Hvare-khshaeta is similarly associated with Ahura Mazda. Even in roman tradition, Jupiter often is only associated with diurnal lightning at most, while Summanus is a deity responsible for nocturnal lightning or storms as a whole.
Dyēus’s name also likely means “the daytime sky”: In Sanskrit as div- (nominative singular dyāus with vrddhi), its singular means “the sky” and its plural means “days”. Its accusative form *dyēm became Latin diem “day”, which later gave rise to a new nominative diēs. The original nominative survives as diūs in a few fixed expressions.
Finnish taivas Estonian taevas, Livonian tōvaz etc. (from Proto-Finnic *taivas), meaning “heaven” or “sky,” are likely rooted in the Indo-European word. The neighboring Baltic Dievas or Germanic Tiwaz are possible sources, but the Indo-Iranian *daivas accords better in both form and meaning. Similar origin has been proposed for the word family represented by Finnish toivoa “to hope” (originally “to pray from gods”).
Diana is an adjectival form developed from an ancient *divios, corresponding to later ‘divus’, ‘dius’, as in Dius Fidius, Dea Dia and in the neuter form dium meaning the sky. It is rooted in Indoeuropean *d(e)y(e)w, meaning bright sky or daylight, from which also derived the name of Vedic god Dyaus and the Latin deus, (god), dies, (day, daylight), and “diurnal” (daytime).
On the Tablets of Pylos a theonym διϝια (diwia) is supposed as referring to a deity precursor of Artemis. Modern scholars mostly accept the identification. The ancient Latin writers Varro and Cicero considered the etymology of Dīāna as allied to that of dies and connected to the shine of the Moon.
The celestial character of Diana is reflected in her connection with light, inaccessibility, virginity, and her preference for dwelling on high mountains and in sacred woods. Diana therefore reflects the heavenly world (diuum means sky or open air) in its sovereignty, supremacy, impassibility, and indifference towards such secular matters as the fates of mortals and states. At the same time, however, she is seen as active in ensuring the succession of kings and in the preservation of humankind through the protection of childbirth.
The persona of Diana is complex and contains a number of archaic features. According to Georges Dumézil it falls into a particular subset of celestial gods, referred to in histories of religion as frame gods. Such gods, while keeping the original features of celestial divinities, i.e. transcendent heavenly power and abstention from direct rule in worldly matters, did not share the fate of other celestial gods in Indoeuropean religions—that of becoming dei otiosi or gods without practical purpose, since they did retain a particular sort of influence over the world and mankind.
According to Dumezil the forerunner of all frame gods is an Indian epic hero who was the image (avatar) of the Vedic god Dyaus. Having renounced the world, in his roles of father and king, he attained the status of an immortal being while retaining the duty of ensuring that his dynasty is preserved and that there is always a new king for each generation.
The Scandinavian god Heimdallr performs an analogous function: he is born first and will die last. He too gives origin to kingship and the first king, bestowing on him regal prerogatives. Diana, although a female deity, has exactly the same functions, preserving mankind through childbirth and royal succession.
James G. Frazer links Diana with the male god Janus as a divine couple. Frazer identifies the two with the supreme heavenly couple Jupiter-Juno and additionally ties in these figures to the overarching Indoeuropean religious complex. This regality is also linked to the cult of trees, particularly oaks. In this interpretative schema, the institution of the Rex Nemorensis and related ritual should be seen as related to the theme of the dying god and the kings of May.
Dingir (usually transliterated diĝir, pronounced /diŋir/) is a cuneiform sign, most commonly the determinative for “deity” although it has related meanings as well. As a determinative, it is not pronounced, and is conventionally transliterated as a superscript “D” as in e.g. DInanna. Generically, dingir can be translated as “god” or “goddess”.
The sign in Sumerian cuneiform DIĜIR by itself represents the Sumerian word an (“sky” or “heaven”), the ideogram for An or the word diĝir (“god”), the supreme deity of the Sumerian pantheon. In Assyrian cuneiform, AN, DIĜIR could be either an ideogram for “deity” (ilum) or a syllabogram for an, or ìl-. In Hittite orthography, the syllabic value of the sign was again an.
The concept of “divinity” in Sumerian is closely associated with the heavens, as is evident from the fact that the cuneiform sign doubles as the ideogram for “sky”, and that its original shape is the picture of a star. The original association of “divinity” is thus with “bright” or “shining” hierophanies in the sky.
The Sumerian sign DIĜIR originated as a star-shaped ideogram indicating a god in general, or the Sumerian god An, the supreme father of the gods. Dingir also meant sky or heaven in contrast with ki which meant earth. Its emesal pronunciation was dimer.