The adjective ᴹQ. tumba “deep, lowlying” appeared in rough (and ultimately rejected) notes on irregular verbs from the Quenya Verbal System of the late 1940s as a derivative of ᴹ√TUB “fall low, go down” (PE22/127). In a 1961 letter to Rhona Beare tumba was glossed “deep valley” as an element in the Entish phrase Q. Taurelilómëa-tumbalemorna Tumbaletaurëa Lómëanor “Forestmanyshadowed-deepvalleyblack Deepvalleyforested Gloomyland” (Let/308; LotR/467), but I think this is only an approximate translation, and the word is better understood as adjectival in sense: “✱like a deep valley”. As further evidence of this, in notes from the late 1960s the form tumba was changed to a more typical noun form Q. tumbo in the name Q. i Tumbo Tarmacorto “the Vale of the High Mountain Circle” (NM/351).
Neo-Quenya: For purposes of Neo-Quenya, I’d treat this word as an adjective only, and use Q. tumbo for the noun.
The adjective ᴹQ. tumba “deep, lowlying” appeared in rough (and ultimately rejected) notes on irregular verbs from the Quenya Verbal System of the late 1940s as a derivative of ᴹ√TUB “fall low, go down” (PE22/127). In a 1961 letter to Rhona Beare tumba was glossed “deep valley” as an element in the Entish phrase Q. Taurelilómëa-tumbalemorna Tumbaletaurëa Lómëanor “Forestmanyshadowed-deepvalleyblack Deepvalleyforested Gloomyland” (Let/308; LotR/467), but I think this is only an approximate translation, and the word is better understood as adjectival in sense: “✱like a deep valley”. As further evidence of this, in notes from the late 1960s the form tumba was changed to a more typical noun form Q. tumbo in the name Q. i Tumbo Tarmacorto “the Vale of the High Mountain Circle” (NM/351).
Neo-Quenya: For purposes of Neo-Quenya, I’d treat this word as an adjective only, and use Q. tumbo for the noun.