A word for “son” in the Qenya Lexicon of the 1910s with variants hilu and hilmo under the early root ᴱ√HILI (QL/40), both variants also appearing in the Poetic and Mythological Words of Eldarissa (PME/40).
Early Quenya
vondo
noun. son
fion
noun. son
hilmo
noun. son
hilu
noun. son
ion
noun. son
In the Qenya Lexicon of the 1910s, ᴱQ. Ion was the “mystic name of God, 2nd Person of Blessed Trinity”, that is the “Son” in the “Father, Son, Holy Ghost” trinity (QL/43). In that document yon or yond- was given in a couple of places as (archaic?) words for “son” (QL/43, 106). In Early Noldorin Word-lists of the 1920s, Tolkien gave ion as the equivalent of ᴱN. gó “son”, along with a plural form yondi (PE13/113). However, in the English-Qenya Dictionary Tolkien said yondi was an irregular plural form of ᴱQ. yondo “son” (PE15/77), and this is the form he typically used in later writings.
vô
noun. son
yon
noun. son
yó
noun. son
A word glossed {“nephew” >>} “son” in an isolated entry of the Qenya Lexicon of the 1910s with stem form fiond- (QL/37). The same word appeared unglossed under the early root ᴱ√SUẈU where it was derived from primitive ᴱ✶þẉ-iı̯on-d (QL/87).