ilwë noun "sky, heavens" (LT1:255), "the middle air among the stars" (LT1:273). VT49:51, 53 also mentions an obscure prononominal element ilwë.
Quenya
hellë
sky
ilwë
sky, heavens
alassë
joy, merriment
alassë (1) noun "joy, merriment" (GALÁS) [VT42:32; a gloss "mirth" was deleted, VT45:14]
alassëa
`Cな#,F`C adjective. happy, joyous
Alassë (joy/merriment) + -a (adjectival suffix)
hellë noun "sky" (3EL; a distinct word hellë "frost" was struck out, see KHEL.)