telluma noun "dome, copula", especially the "Dome of Varda" over Valinor, but also applied to the domes of the mansion of Manwë and Varda upon Taniquetil. Adopted from Valarin _delgūmā under the influence of pure Quenya telumë (WJ:399, 411). Pl. tellumar is attested (Nam, RGEO:66)_.
Quenya
telluma
noun. dome, cupola, vault
telluma
dome, copula
telumë
dome, roof, canopy
telumë noun "dome, roof, canopy" (TEL/TELU, WJ:411 cf. 399; see also telluma); "firmament" (MC:214), inflected telumen in MC:221 (the latter is "Qenya"). Telumehtar "warrior of the sky", older name of Menelmacar = Orion (Appendix E, TEL/TELU, WJ:411); Telumendil *"Sky-friend", name of a constellation (Silm)
A word for a “vault” or “dome” in the Namárië poem (LotR/377; RGEO/58). In the Quendi and Eldar essay from 1959-60, Tolkien said telluma “dome, cupola” was an alteration of telumë under the influence of the Valarin word Val. delgūmā “dome”, used “especially the ‘Dome of Varda’ over Valinor, but also applied to the domes of the mansion of Manwe and Varda upon Taniquetil” (WJ/399, 411). As such, this word may not have been in common use, being applicable only to the “holy domes” of the Valar.