We're using the English word "meditation", which comes to us from the Latin, dates from about 1200, and therefore seems likely to have its roots in Christian spiritual practices.
As far as I know the connection of the word "meditatio" to the practice of e.g. za zen and other comparable practices stems from Christians who found the practices they experienced in China or Japan to be similiar to their own spiritual practice that was called "meditatio".
So when they integrated them they were also labeled "meditatio".
It were those christians who brought spiritual practices like za zen to Europe as part of their own christian meditatio long before those practices started their own, independent history in the west.
I think it is important not to narrow the understanding of what meditation means in the context of aikidō too much.
I myself practiced za zen years ago. I'm now doing a form of meditation which is related to nei gong. And forms of christian meditation accompany me all the time.
My direct teacher practices forms of shintō and also shingon buddhism.
Our shihan is doing za zen.
A dohai of me practices christian meditation very intensively.
Another friend does something I don't know and don't understand like meditating with trees and things like that.
To me all this is "medititation". All this is connected to the practice of aikidō within the persons who practice one to nurture the other.