Name of the “Doors of Night” leading beyond the world in Silmarillion drafts from the 1930s (SM/237, 241), also appearing as a rejected name in The Etymologies as combination of ando “door” and the genitive of lóme “night” (EtyAC/LOƷ).
Qenya
ando
adverb. long
ando lómen
proper name. Door of Night
anda
adjective. long
-ando
suffix. agent (male)
hando
noun. agent (male)
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).