The most common Quenya suffix for “daughter of” such as in Elerondiel “✱Daughter of Elrond” (PE17/56) or Uinéniel “Daughter of Uinen” (UT/182).
Conceptual Development: The earliest hint of this suffix was ᴱQ. -il mentioned by Tolkien in the Qenya Lexicon of the 1910s as the equivalent of feminine patronymic ᴱQ. -wen (QL/103), but its only use in this period was in the masculine name ᴱQ. Indorildo, a variant of ᴱQ. Indorion and hence probably meaning “son of” (LT2/217). In The Etymologies of the 1930s Tolkien mentioned ᴹQ. -iel as a feminine patronymic under the root ᴹ√YEL “daughter” (Ety/YEL¹), but this root was rejected and in that document Tolkien seems to have replaced it with ᴹQ. -ien (EtyAC/YŌ).
In later writings Tolkien considered a bewildering variety of suffixes for the feminine patronymic, including -iel(d), -well, -wend and -ien (PE17/170, 190). In practice, though, only -iel appeared in actual names for “daughter of” (see above), perhaps because it is was the cleanest equivalent of the well-established masculine patronymic -ion “son of”.
-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.