I do love a good crackpot — excuse me, I mean premodern — etymology, and Poemas del río Wang has a doozy; the quote is from “the eleven-language dictionary of Calepinus, published in 1590 in Basle, which I happen to have here on my bookshelf” (“I found this bulky folio volume some thirty year ago in a waste paper recycling shop, and purchased it at the price of scrap paper, for about one euro in today’s currency”):
It is not unworthy to consider, that almost every people and language writes the name of God in four letters. In fact, the Hebrews call him יחוח Yehova, with four letters, the Chaldeans also with four letters, אלוח Eloha, the Syriacs also אלוח Eloha; at the Aethiopians He is אמלו Amlau, at the Assyrians אדעד Adad, at the Greeks Θεός, at the Egyptians Θωύθ, at the Persians Σύρη, at the Latins Deus, at the Italians Idio, at the Spanish Dios, at the French Dieu, at the Germans, Flemish and English Gott or Godt, at the [Persian] Magi Orsi, at the Poles Boog, from bog, that is, ʻfear’, at the Dalmatians and Illyrians Boga or Boog, at the older Muslims, whom we also call Saracens, Abgd, at the Turks following Mohamed Alla, at the peoples discovered in the world called “new” Zimi, at the Vlachs Zëul, at the Gypsies Odel.
At the Hungarians, if we look at its origin, the name of God has also four letters. They call him with great respect Isten, which, although seems to have five letters, if we consider its origin, has only four. In fact, the Hungarian term comes from the second aorist of the verb ʻto be’ ἴστημι, which sounds ἐϛὶν [ἐστὶν]: ʻI exist, I am by way of myself’, which second aorist is written with four letters. The s and t, written with two letters in the Hungarian word, are both encompassed in the single Greek letter ϛ sigmatau. Thus, by virtue of its origin, the Hungarian name also has to be written with four letters, so: Ἴϛεν [Ἴστεν]. In this way, the name of God is a τετραγράμματον [four-letter name] for every people, and we think He is called so, because His essence is one, but within His one essence He is three actually existing and different persons.”
You can see an image of the Calepinus page at the link, where you will also find a discussion of the actual etymology of Hungarian isten (about which there are various opinions).