The Adûnaic word for God (SD/432), the equivalent of Q. Eru, though Tolkien had not yet coined that name. In the conceptual development of this name, Tolkien first invented it as an Adûnaic word (SD/312), only later adding it to Quenya. In this revised scenario, it is likely that the Adûnaic word was a loan word from Elvish. See Ad. Amân for a similar development.
êrumasculine name. God (the Omnipotent)
tâidôadverb. once, then
An adverb glossed as both “once” and “then” (SD/247, VT24/12). Several authors have suggested (AAD/23, EotAL/TA3) that the final element may be îdô “now”. Andreas Moehn suggested (EotAL/TA3) the initial element tâ is a marker that puts it into the past: îdô = “now”, tâ-îdô = “previous time” = “then”. It seems likelier to me that the prefix is related to the Eldarin demonstrative root √TA “that, there, then”, as suggested by Carl Hostetter and Patrick Wynn (AAD/23): tâ-îdô = “that time” = “then”.
Conceptual Development: In the second draft of the Lament of Akallabêth, this word was ēluk (SD/312).