the Japanese languages has many homophones.
It is known, that karate moved its meaning from KARA-te (Chinese Boxing) to kara te (empty hand fight). So maybe the original meaning of aikido was totally different?
I'm not very familiar with the Japanese language nad I do not know, how to create the right kanji and kana on machine. So I just do a simple start I write just the romaji and give the number of the knji I have found (first should be the official launched by the ministry, second is from Nelson's japanese English Character Dictionary)
ai- (146;2241) (opposite, two-way)
KI (135;2507) steam
(149;4724), as we all know
this could mean that it was the way , how one could punch each other with full steam - or so.
I don't know, if my metaphor is taken well, in German steam also stands for force, since the first steam engines.
But you all can find better examples, it can also be "a i ki do". And this is the humor section, so feel free for brain storming. Nevertheless there is a chance that someone will take us serious and comes back with a historically undermined article
Waiting for good and funny ideas
And if we are ready with this we can go back to further mutations, i.e. take other readings of a symbol use the other meaning and then finally find homophones to those.