If you find any Aikido books that are not going to make the migration- I'll send you shipping to "chuck" them my way!
That one went to the sea voyage pile.
With respect to the term Aiki - I doubt that even in historical times, in cultural context, it had any clear meaning. Much as I like and can relate to some of those historical definitions the terms use was more broad - almost like a catch-all. Ueshiba if anything was even less precise.
For anyone to say what Ueshiba actually meant requires a lot of assumption (presumption).