A noun in the Qenya Lexicon of the 1910s glossed “river” derived from the root ᴱ√SIŘI [SIÐI] (QL/84). The same word appeared in the contemporaneous Poetic and Mythological Words of Eldarissa (PME/84).
Early Quenya
hir
noun. inwards, interior, inside, heart
hi
pronoun. she; 3rd sg. fem. pronoun
heri
noun. lady
heruni
noun. lady
heru
noun. lord
i-
prefix. she; 3rd sg. fem. pronoun
int
adverb. inwards
ion
masculine name. *Christ
sindi
noun. river
sirion
place name. Sirion
turanwen
noun. princess
turille
noun. princess
turwen
noun. princess
tye
pronoun. you
In the Qenya Lexicon from the 1910s, given as the “mystic name of God [as the] 2nd person of Blessed Trinity” (QL/43), hence = “Christ”. It was derived from yó “son” (QL/106).