A word for “roof, canopy” appearing in the Quendi and Eldar essay from 1959-60 derived from √TELU “roof in, put the crown on a building” (WJ/399, 411). Tolkien said it “was probably one of the earliest Quendian words for the heavens, the firmament, before the increase of their knowledge, and the invention of the Eldarin word Menel” (WJ/411). As such, it was only used for “heavens” metaphorically, in mythical names like Telumehtar “Warrior of the Sky”, the Quenya name of the Orion constellation (LotR/1113; WJ/411).
Conceptual Development: The first precursor to this word seems to be ᴱQ. telimbo “canopy, often used = sky” under the early root ᴱ√TELE “cover in” (QL/90). This became ᴱQ. telume “heavens, vault of heaven, firmament” in Qenya poems written around 1930 (MC/214, 221; PE16/142). In the Declension of Nouns of the early 1930s it was ᴹQ. telume “vault, heaven” (PE21/16) and in The Etymologies of the 1930s it was glossed “dome, (especially) dome of heaven” under the root ᴹ√TEL(U) (Ety/TEL).
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)