Suggestions for translation?

I can't find any terms for it, so does anyone have suggestions for how one might refer to the Northern Lights/Aurora Borealis in either Sindarin or Quenya? I feel like it would either need to be a direct translation of "northern lights" or a descriptive term of some kind. Like how aurora borealis is basically "northern morning light," something with flowing light maybe?

My understanding of elven word combinations/grammar is extremely shaky, so any suggestions for how someone might translate this is appreciated!

A direct translation of “northern lights” to Quenya would be Fornë Calar or perhaps a compound Forcalar (to correspond with the southern Hyarnë Calar, Hyarcalar).

In Sindarin I’d say Calad Forn or compounds Forchalad, For(o)chal with corresponding southern Calad Charn and Harchalad, Har(a)chal. Note that these are subject to all the usual mutations in Sindarin grammar, so calad “light” > i galad “the light,” etc.

There’s certainly room for more poetic or descriptive options — e.g. using Q. alcar / S. aglar “glory, radiance, brilliance” from the same ancient root as the general words for “light” above — but these are probably good starting points.

Thank you, this is super helpful!

Going for a more poetic option, as you suggested, would it be possible in Quenya to combine alcar with celumë? To get a meaning along the lines of flowing/streaming radiance/light? Or would you use a different term?

My other thought was a meaning of "dancing light" which I think would need to use Q. lilta, though I'm unsure how you would use that in a compound word.

Thank you again!

A combination *Alcarcelumë would mean “Glory-stream” (and is a bit long for a Quenya compound besides), so I wouldn’t recommend it for this meaning.

Other compound options from the root √KEL:

• Celcalar “Streaming Lights”
• Celcálë “Streaming Light”
• Celalcar “Streaming Glory” (/splendor/radiance/brilliance)

And from √SIR:

• Sircalar “Flowing Lights”
• Sircálë “Flowing Light”
• Siralcar “Flowing Glory” (as above)

Re: “dancing lights,” I wouldn’t use the verbal stem lilta- in a compound, but I think we can extrapolate a late-concept root *√LIL from given materials to incorporate: Lilcalar, Lilcálë, Lil(t)alcar, etc. A phrasal translation would likely be some variant of lilta(i)la cala(r)/cálë.