@@@ Helge Fauskanger suggested that Eldarinwa is an extended form of this word as an adjective (QQ/Eldarin). More exactly, I think it is the application of the possessive/adjectival suffix -va to the word Eldarin in its noun-sense = “Elvish language”.
Quenya
Eldarin
eldarin, elvish
eldarin
noun/adjective. of the Eldar; Elvish (language)
tárion
noun. alternate name of the last day of the Eldarin six-day week
Valinor
the land (or people) of the valar
Valinor place-name "the land (or people) of the Valar", *"Vali-land" (Vali = Valar), land of the Gods in the West (BAL, NDOR); cf. Valandor. Full form Valinórë (BAL; Vali-nórëunder NDOR).Said to be "the true Eldarin name of Aman", the latter name being explained as a borrowing from Valarin in some versions of the linguistic scenario (VT49:26). In the early "Qenya Lexicon", Valinor, Valinórë is glossed "Asgard", the name of the city of the gods in Norse mythology (LT1:272). It seems that in such more restricted use, Valinor is not the entire Blessed Realm but rather the specific region beyond the Pelóri where (most of) the Valar dwelt, with Val(i)mar as the chief city. Thus it is said of Eärendil that he "went into Valinor and to the halls of Valimar" only after he had already left his ship and ventured as far as Tirion (Silmarillion, chapter 24). Possessive Valinóreva in Nurtalë Valinóreva, the "Hiding of Valinor", the possessive case here assuming the function of object genitive (Silm); genitive Valinórëo in Yénië Valinórëo "Annals of Valinor" (MR:200; the last word was changed from Valinóren, Tolkien revising the genitive ending from -n to -o)
alda
tree
alda noun "tree" (GALAD, GÁLAD, SA, Nam, RGEO:66, LR:41, SD:302, LT1:249, LT2:340, VT39:7), also name of tengwa #28 (Appendix E). Pl. aldar in Narqelion; gen. pl. aldaron "of trees" in Namárië. Etymology of alda, see Letters:426 and UT:266-7. The latter source states that primitive ¤galadā, whence Quenya alda, originally applied to stouter and more spreading trees such as oaks or beeches, while straighter and more slender trees such as birches were called ¤ornē, Quenya ornë - but this distinction was not always observed in Quenya, and it seems that alda became the general word. According to PE17:25, primitive galada (sic) referred to "a plant (large) and was a general term". Place-name Aldalómë ""tree-night" or "tree-shade-night" (LotR2:III ch. 4, translated in PE17:82); Aldarion masc. name, *"Son of (the) Trees" (Appendix A), Tar-Aldarion a Númenorean King (UT:210). Aldaron a name of Oromë (Silm); aldinga "tree-top" (VT47:28), aldarembina (pl. aldarembinë attested) adj. "tree-tangled", the cognate of Sindarin galadhremmin**(PM:17:26).Aldúya fourth day of the Eldarin six-day week, dedicated to the Trees (Appendix D). The word seems to include Aldu, a dual form referring to the Two Trees. The Númenóreans altered the name to Aldëa (presumably < aldajā), referring to one tree (the White) only. The dual Aldu seems to occur also in Aldudénië** "Lament for the Two Trees" (a strange word, since Quenya does not permit intervocalic d as in this word perhaps the Vanyarin dialect of Quenya did) (Silm)
alda
noun. tree
alda
noun. tree, tree, [ᴱQ.] branch
The basic Quenya word for “tree” (LotR/1113), derived from primitive ✶galadā and very well attested. This word dates all the way back to the Qenya Lexicon of the 1910s where ᴱQ. alda “tree” appeared under the early root ᴱ√ALA “spread” (QL/29). Tolkien seems to have switched its derivation to ✱galadā in The Etymologies of the 1930s, where ᴹQ. alda “tree” appeared under the root ᴹ√GALAD of the same meaning (Ety/GALAD). See also ornë “(tall) tree” for a discussion of another similar word.
Conceptual Development: There were a few instances where the word alda had a different meaning. In Early Qenya Word-lists of the 1920s, alda was glossed “branch” (PE16/139). In notes from 1959 Tolkien said “✱galadā, originally only large flourishing plant, as tree, and especially one that flowered, Q alda, S galað; the general word for ‘tree’ was Q orne ‘upstanding plant’ (PE17/153)”. But in its numerous appearance elsewhere, alda was simply a general word for “tree”.
ornë
tree
ornë noun "tree" _(Letters:308, SD:302: "when smaller and more slender like a birch or rowan", Etym stem ÓR-NI: "tree, high isolated tree"). For the etymology, see Letters:426; for (original) difference in meaning between ornë and alda, see alda. In ornemalin "tree-yellow"; see laurelindórenan lindelorendor... (LotR2:III ch. 4; cf. Letters:308), also as final element in malinornë "yellow-tree, mallorn" (q.v.) Masc. name Ornendil *"Tree-friend" (Appendix A)_, compound Ornelië "tree-folk" (Quenya name of the Galadhrim, the tree-people of Lórien) (TI:239).
quenelya
adjective. of the Elves
Eldarin adj. derived from Elda: "Eldarin, Elvish" (Silm, ÉLED). Also in the longer form Eldarinwa (pl. Eldarinwë in VT47:14, in the title Eldarinwë leperi ar notessi, "The Eldarin fingers and numerals")