The Greek Names of God are Θεὸς/Theos/God and Κύριος/ Kurios/Lord. 1. The former Greek name of God, Θεὸς/Theos, among the Gentiles was used of old to designate their fictitious God, before it was used in the Septuagint Version or the New Testament of the true God. Its origin is indicated in diverse ways. It is derived from θεάομαι, to gaze upon, in GREGORY NYSSEN’S tractate, Quod non sint tres Dii, opera, tome 3, pages 19, 20, which denotes to contemplate, to regard; and thus it is able to indicate the divine Omniscience: you read in Gregory, Ὑπειλήφαμεν ἐκ τῆς θέας, τὴν θεότητα παρωνομάσθαι, καὶ τὸν θεατὴν ἡμῶν Θεὸν, ὑπὸ τε τῆς συνηθείας καὶ τῆς τῶν γραφῶν διδασκαλίας προσαγορεύεσθαι, etc., we suppose that from θέα/ beholding the θεότης/Godhead is named, and that He who is our θεατής/ Beholder by custom and by the teaching of the Scriptures is called Θεὸς/ Theos, etc. It is derived from τίθημι, to set or establish, in CLEMENT OF ALEXANDRIA, at the end of book I of his Stromata, page 357, where it is referred to the divine Creation and ordination of all things: Clement says in this place, Θεὸς δὲ παρὰ τὴν θέσιν εἴρηται καὶ τάξιν, τὴν διακόσμησιν, but He is called Θεὸς/God from θέσις/placing and order or arrangement. The derivation of Θεοῦ/God from θέειν, to run, is indeed able to be applied to the true God, and denotes His perpetual activity, concerning which John 5:17, just as one that runs abides in perpetual motion: as THEOPHILUS, ad Autolycum,[1] book I, page m. 71, conjoins the Etymology of the word Θεὸς/God from τίθημι, to set or establish, and θέειν, to run, and explains both in a good sense, Θεὸς δὲ λέγεται, διὰ τὸ τεθεικέναι τὰ πάντα ἐπὶ τῇ ἑαυτοῦ ἀσφαλεὶᾳ, καὶ διὰ τὸ θέειν· τὸ δὲ θέειν ἐστὶν τὸ τρέχειν, καὶ κινεῖν, καὶ ἐνεργεῖν, καὶ τρέφειν, καὶ προνοεῖν, καὶ κυβερνᾶν, καὶ ζωοποιεῖν τὰ πάντα, and He is called Θεὸς/God, on account of His τεθεικέναι, having placed/ established, all things upon His own security; and on account of θέειν, for θέειν is to run, and to set in motion, and to be active, and to nourish, and to foresee, and to govern, and to make all things alive. But it is more probable that Pagan Idolaters imposed the name of θεῶν/gods from θέειν, to run, upon the same from the perpetual course of the stars, which were venerated as Deities. CLEMENT OF ALEXANDRIA, Protreptico, page 16, speaking of the origin of Idolatry, says of men: Οἱ μὲν γὰρ εὐθέως ἀμφὶ τὴν οὐρανοῦ θέαν ἀπατούμενοι, καὶ ὄψει μόνῃ πεπιστευκότες, τῶν ἀστέρων τὰς κινήσεις ἐπιθεώμενοι, ἐθαυμασάντε, ἐξεθείασαν, Θεοὺς ἐκ τοῦ θεῖν ὀνομάσαντες τοὺς ἀστέρας, for some, beguiled by the θέα/spectacle of the heavens, and having trusted in their sight alone, were immediately seized with admiration, while gazing upon the motions of the stars, and deified them, calling the stars Θεοί/ Gods, from θεῖν, to move. Likewise EUSEBIUS, Præparatione Euangelica, book I, chapter IX, page 29, out of PLATO’S Cratylus, writes: Φαίνονταί μου οἱ πρῶτοι τῶν ἀνθρώπων τῶν περὶ Ἑλλάδα, τούτους μόνους θεοὺς ἡγεῖσθαι, οὕσπερ νῦν πολλοὶ τῶν βαρβάρων, ἥλιον καὶ σελήνην, καὶ γῆν, καὶ ἄστρα καὶ οὐρανόν· ἅτε οὖν αὐτὰ ὀρῶντες πάντα ἀεὶ ἰόντα δρόμῳ καὶ θέοντα, ἀπὸ ταύτης τῆς φύσεως τῆς τοῦ θεῖν, θεοὺς αὐτοὺς ἐπονομάσαι, it appears to me that the first of the men about Hellas had only the same gods as many of the barbarians have now, sun and moon, earth, stars and heaven: as, therefore, they saw them all always moving on in their course and θέοντα/running, from this their natural tendency θεῖν, to run, they called them θεοὺς/gods. But nothing prevents this word from being transferred to designate the far sublime and Divine Nature. Finally, if you should have regard to δέος/fear in the Name Θεὸς/God, it would denote the terrible Majesty of God to be acknowledged by everyone, whence God is called the Fear of Isaac, Genesis 31:53. It is not true that superstitious and vain Fear first made the gods in the world, as PETRONIUS the Epicurean[2] falsely asserted, Satyrico, page m. 207, but the innate sense of the Divine compels the observation and fear of the actually existing God.
[1] Theophilus (died c. 183) was Bishop of Antioch. His only remaining writing is his Ad Autolycum, in which he presents an apology for the Christian religion and a polemic against paganism. Ad Autolycum is the earliest extant Christian writing to use the word Trinity.
[2] Gaius Petronius Arbiter (c. 27-66 AD) was a Roman courtier, and is believed to the author of the Satyricon, a satirical novel.