An Adûnaic name for Morgoth, perhaps coined by Sauron when he introduced the worship of the dark god to the Númenóreans, translated
as “Lord” (SD/376). It is derived from the word ârû “king” and was sometimes used in a compound together with Morgoth’s true Adûnaic name: Arûn-Mulkhêr (SD/367). In other writings (SD/357) it was the original Adûnaic name of Morgoth before he fell to evil, but that hardly
makes sense in the conceptual scenario of the later Silmarillion, in which Morgoth had already become evil before men awoke.
A rejected draft version of the Adûnaic name for Morgoth translated “Lord”, replaced by Arûn of the same meaning (SD/376). It is transparently a derivative of the Elvish root ᴹ√KHER, as suggested by Carl Hostetter and Patrick Wynn (AAD/18). A later form of this word, *khôr “lord”, may appears as an element in the name Adûnakhôr “Lord of the West”.