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
andave
adverb. *long
andave laita
andave laita
anda
adjective. long
ando
adverb. long
indon
conjunction. as
An adverbial form of anda “long” from the phrase Q. Eldar ando kakainen loralyar Koivienenissen “the Elves were long lying asleep at Koivienéni” (VT27/7).