The correlative ᴹQ. indon “as” appeared in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 (PE23/111), a combination of the relative pronoun ᴹQ. i and the similative suffix ᴹQ. -ndon.
Qenya
oia
adverb/adjective. everlasting
oiakúma
place name. Oiakúma
oira
adjective. eternal
oiale
noun. everlasting age
ia
adverb. ever
oi
adverb. ever
oi-
verb. to live, pass one’s days
iale
noun. everlasting age
indon
conjunction. as
íra
adjective. eternal
Another name for Avakúma appearing in The Etymologies from the 1930s as combination of oia “everlasting” and kúma “void” (Ety/OY, EtyAC/OY).