Quenya 

rauco

powerful, hostile, and terrible creature

rauco ("k") noun "a powerful, hostile, and terrible creature", "very terrible creature", especially in the compound Valarauco noun "Demon of Might" _(WJ:415, VT39:10, cf. SA:raukor. In the Etymologies, stem RUK, the gloss is "demon".)_ Longer variant arauco. The plural form Valaraucar "Balrogs" seems to contain the variant rauca.

rauco

noun. demon, powerful hostile and terrible creature

Quenya [PE17/048; SA/rauko; VT39/10; WJ/415] Group: Eldamo. Published by

rauca

demon

rauca ("k")noun "demon" (PE17:48). Variant of rauco, q.v.

rauca

noun. demon

Valarauco

demon of might

Valarauco ("k") noun "Demon of Might" (here vala- assumes its basic meaning "power, might"), Sindarin balrog(WJ:415). Pl. Valaraucar (sic, not -or) "Balrogs", apparently containing rauca (q.v.) as an alternative form of rauco "demon" (SA:val-, SA:rauco). Earlier forms from the "Qenya Lexicon" are Valcaraucë, Malcaraucë (q.v.), apparently abandoned in LotR-style Quenya.

arauco

powerful, hostile, and terrible creature; demon

arauco ("k")noun "a powerful, hostile, and terrible creature; demon" (variant of rauco). Tolkien's earlier "Qenya" has araucë "demon" (WJ:415, LT1:250)

arauco

noun. demon