Qos (Hebrew קוס/קוש), also Qōs, Qaus, Koze) was the national god of the Edomites. He was the Idumean rival of Yahweh, and structurally parallel to him. Thus 'son of Qōs' parallels the Hebrew 'Beniyahu' (son of Yahweh). The name occurs only once in the Old Testament (if we exclude a possible allusion in an otherwise corrupted text in the Book of Proverbs) in the Book of Ezra as an element in a personal name, Barqos ('Qōs gleamed forth'), referring to the 'father' of a family or clan of Edomite nĕtînîm or temple helpers returning from the Babylonian exile. The noun frequently appears combined with names on documents recovered from excavations in Elephantine, where a mixed population of Arabs, Jews and Idumeans lived under the protection of a Persian-Mesopotamian garrison.
Qōs may mean bow. It is speculated that this god may have been interchangeable with Yahweh, Baal, Haddu/Hadad and Dushara, these five names being epithets for a common deity. Unlike the chief god of the Ammonites (Milkom) and the Moabites (Chemosh), the Tanakh refrains from expliciutly nominating the Edomite Qōs and Yahweh hailed from Se'ir in the region of Edom. The omission may be explained, according to some scholars, by the close similarity of Yahweh with Qōs, making rejection of the latter difficult. Both Qōs and Yahweh are probably words of Arabic origin, and Knauf and others argue that YHWH is a northern Arabic word, from the Semitic root hwy, meaning "he blows". Knauf concludes that the two are typologically similar, being: