Maiden of Gondolin, beloved of Tuor and mother of Eärendil (S/126). Her name is an adaption of her Quenya name Itarillë (PM/346).
Conceptual Development: This character appeared in the earliest Lost Tales as G. Idril (LT2/164), but in this period she had a second name G. Idhril, and Tolkien vacillated between the two names throughout his life. In the Gnomish Lexicon from the 1910s, Idril was translated “Beloved”, and this was said to be her true name, but she was also known as Idhril “Mortal Maiden” because of her marriage to Tuor (GL/50). In the Silmarillion drafts from the 1930s, her name appeared as N. Idril (SM/36, LR/141), but in The Etymologies it was Idhril, a derivative of ᴹ√ID “desire” (Ety/ID).
Her name was Idril in The Lord of the Rings (LotR/1034), but in Notes on Names (NN) from 1957, Tolkien noted that the form should be Idhril if it were derived from the root √ID (PE17/112). At this point Tolkien devised the new derivation given above, from her Quenya name Itarillë, and this seems to have been his final word on the subject (PM/346).
Irildë fem. name "Idhril" (Idril) (LT2:343), #Írildë (J.R.R. Tolkien: Artist & Illustrator p. 193), Írildë also as name of a Númenorean woman (UT:210). Irildë Taltyelemna = (later) Sindarin Idril Celebrindal;replaced Irildë Taltelepsa (KYELEP/TELEP; Taltelemna in the Etymologies as printed in LR is an error for Taltyelemna, VT45:25). Tolkien seems to have replaced Irildë as the Quenya form of Idril with Itaril, Itarillë, Itarildë, q.v., in which case the Sindarin form is definitely Idril and not Idhril.