Quenya 

hellë

sky

hellë noun "sky" (3EL; a distinct word hellë "frost" was struck out, see KHEL.)

ilwë

sky, heavens

ilwë noun "sky, heavens" (LT1:255), "the middle air among the stars" (LT1:273). VT49:51, 53 also mentions an obscure prononominal element ilwë.

nixë

frost

nixë noun "frost" (WJ:417); previously described as a synonym of niquis "ice-flake or snowflake", q.v. (PE17:168)

Noldorin 

hell

noun. frost

A noun in The Etymologies of the 1930s glossed “frost” derived from the root ᴹ√KHEL “freeze”, but Tolkien deleted this short root and its derivatives, keeping only the longer form ᴹ√KHELEK (Ety/KHEL).

Conceptual Development: The Gnomish Lexicon of the 1910s had a number of similar “frost” related words: G. heloth “frost”, G. hîl {“ice-cold, icy” >>} “frost” as well as G. helfileg “frost on panes, etc.” (GL/48-49), all based on the early root ᴱ√HELE “freeze”, the last with the added element G. fileg “fern”.

Neo-Sindarin: Tolkien probably deleted N. hell “frost” because he abandoned the short root ᴹ√KHEL, but short √KHEL did reappear in later writings (PE17/116), so it is tempting to restore hell “frost” as well. However, this conflicts with other attested words like N. hell “naked”, so I think it is better to use a neologism like ᴺS. nich for “frost”; see that entry for discussion.

Noldorin [Ety/KHEL] Group: Eldamo. Published by

ell

noun. sky

An element meaning “sky” in several names from The Etymologies of the 1930s: N. Elfaron “Sky-hunter” (Ety/SPAR) and N. Elthoron “Eagle of the Sky” (Ety/THOR). It was derived from the root ᴹ√ƷEL “sky” which had an Old Noldorin form: ON. elle (Ety/ƷEL). However, Tolkien said “In Noldorin and Telerin this is confused with EL star”, implying that the word was not used in modern language; an earlier but rejected version of this entry had archaic N. †ell, el “sky” (EtyAC/ƷEL).

Neo-Sindarin: Despite the above statements, ell is probably the best attested option for “sky” in Neo-Sindarin, and I would use it as such, since it is in fact distinct from S. êl “star”, a word that is itself archaic/poetic versus more common S. gil.

Noldorin [Ety/SPAR; Ety/THOR; EtyAC/ƷEL] Group: Eldamo. Published by

Sindarin 

hell

9j¸$ noun. frost

Sindarin [Etymologies] Group: Subject of debate. Published by

Menel

noun. sky, high heaven, firmament, the region of the stars

Sindarin [LotR/II:I, LotR/IV:X, LB/354, RGEO/72, VT/44:21,] Q menel. Group: SINDICT. Published by

nich

noun. frost

A neologism for “frost”, cognate of Q. nixë of the same meaning (WJ/417), that assumes a phonetic development similar to that of S. ach vs. Q. akse (axë) “neck” (PE17/92); see the entry on how [[os|[p], [t], [k] spirantalized before [s]]] in (Old) Sindarin.

Sindarin Group: Eldamo - neologism/reconstructions. Published by

Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!

Qenya 

helle

noun. sky

A noun in The Etymologies of the 1930s glossed “sky” derived from the root ᴹ√ƷEL of the same meaning (Ety/ƷEL).

helle

noun. frost

helor

noun. frost

Old Noldorin 

elle

noun. sky

Old Noldorin [Ety/ƷEL] Group: Eldamo. Published by

el

noun. sky

Old Noldorin [Ety/ƷEL] Group: Eldamo. Published by

Middle Primitive Elvish

ʒel

root. sky

A root in The Etymologies of the 1930s glossed “sky”, with derivatives like ᴹQ. helle/N. ell “sky” and ᴹQ. helwa/N. elw “(pale) blue” (Ety/ƷEL). It was the basis for the initial elements of the names N. Elrond, N. Elwing and ᴹQ. Elwe, but elsewhere Tolkien connected these names to √EL “star”. It was also an element in the word N. eilian(w) “rainbow, (lit.) sky-bridge”, later given as S. ninniach. On the basis of these changes, I think it is likely Tolkien abandoned ᴹ√ƷEL, but some of its derived words are still popular in Neo-Eldarin.

Middle Primitive Elvish [Ety/ƷEL; Ety/YAT] Group: Eldamo. Published by

Doriathrin

gell

noun. sky

A Doriathrin noun for “sky” derived from the root ᴹ√ƷEL (Ety/ƷEL), probably from a primitive form ✱✶ʒellē [ɣellē] based on its cognates. It is a clear example of how [[ilk|initial [ɣ] became [g]]] in Ilkorin.

Doriathrin [Ety/ƷEL] Group: Eldamo. Published by

Gnomish

dai

noun. sky

Gnomish [GL/29; LT1A/Telimektar; PE13/112] Group: Eldamo. Published by

heloth

noun. frost

Gnomish [GL/48; GL/49; LT1A/Helkar] Group: Eldamo. Published by

hîl

noun. frost

ilon

noun. sky

A word for “sky” in an early name list from the 1910s and appearing in a couple early names: G. Thlim Quing Ilon “✱Folk of the Heavenly Arc” and G. Cris o Teld Quing Ilon “Gully of the Rainbow Roof” (PE13/101, 104), the latter revised to G. Cris Ilbranteloth (LT2/202). In the contemporaneous Gnomish Lexicon, however, G. Ilon was the name of Ilúvatar (GL/50).

Gnomish [LT2A/Teld Quing Ilon; PE13/104; PE15/27] Group: Eldamo. Published by

luithon

noun. sky

A word for “sky” in the Gnomish Lexicon of the 1910s, an elaboration of G. lui “blueness” (GL/55).

Early Noldorin

telum

noun. sky, sky; [G.] roof

Early Noldorin [PE13/153] Group: Eldamo. Published by

Early Quenya

taime

noun. sky

A word for “the sky” in the Qenya Lexicon of the 1910s, with variants Taime and Taimie from the early root ᴱ√TAHA [DAHA] (QL/87). ᴱQ. tea “sky” from Early Qenya Word-lists of the 1920s is probably related, as suggested by Patrick Wynne and Christopher Gilson (PE16/142).

Early Quenya [LT1A/Telimektar; PE16/142; QL/088] Group: Eldamo. Published by

taimie

noun. sky

tea

noun. sky