A name for the Uttermost West as a region, appearing in the Namárië poem (LotR/377). It is simply andúnë “sunset, west” used as a proper name.
Adûnaic
adûni
noun. the West
adûni
noun. the West
adûni
proper name. Westron
andúnë
place name. The West
annúnaid
proper name. Westron
The Sindarin name for the “Westron” language (PM/316). Its initial element is clearly annûn “west”, but the meaning of the suffix -aid is unclear. It might be some variation on the gerund-suffix -ed/-ad seen in nouns like genediad “reckoning”, though this suffix usually forms nouns from verbs, not adjectives. Vyacheslav Stepanov suggested the final element might be from ancient adjectival ✱-etya based on √ET “out”, so that -aid = “✱out from”, as in “✱out from the West”.
annúnaid
noun. the "Westron" language (one of the names for Common Speech)
annúnaid
westron
(a language) Annúnaid
annúnaid
westron
According to Tolkien, this is the proper noun form of the adjective adûn “west” (SD/435), though adûn is used as a noun in some examples as well.