A root in The Etymologies of the 1930s glossed “yawn, gape” with several derivatives such as ᴹQ. assa/N. gas “hole” and N. gaw “void” (Ety/GAS). The names based on this root like N. Belegast and ᴹQ. Ilmen-assa do not appear in later versions of the Legendarium, so the eventual fate of this root is uncertain, especially given that there are other roots of similar meaning like ᴹ√YAG “yawn, gape” (Ety/YAG) that do reappear later (Let/383; PE17/35, 42).
Neo-Eldarin: For purposes of Neo-Eldarin, derivatives of this root are among the best attested words for “hole”, so it’s probably best to retain ᴹ√GAS and its derivatives in Neo-Eldarin writing.