Daughter of king Ondoher and wife of Arvedui (LotR/1049), her name is a compound of Feir “mortal” and the feminine suffix -iel meaning “Mortal Maid” (Ety/PHIR).
Conceptual Development: In Tolkien’s unfinished story “The Lost Road” from the 1930s, the name Fíriel was given to a Númenórean maiden (LR/62). In The Etymologies from the 1930s, the name appeared as a name of Lúthien, with the gloss and etymology given above (Ety/PHIR).
fair (“mortal”) + iell (“daughter, child” [Etym. SEL-D] traditional ending for women’s names)