Quenya 

-iel

daughter

-iel patronymic/matronymic ending -"daughter" (YEL, VT46:22-23) In the Etymologies, Tolkien struck out this ending and the corresponding independent word yeldë "daughter", changing them to -ien, yendë. However, the ending -iel later turns up in later forms: Uinéniel "Daughter of Uinen" in UT:182 and Elerondiel "daughter of Elrond" (Elerondo) in PE17:56. Hence it would seem that Tolkien changed his mind again and restored this ending, and perhaps the noun yeldë along with it. The form Elerondiel (from Elerondo) demonstrates that a final vowel is omitted before -iel.