Show of Force

So, let's see. Bath was entirely outstanding; a lovely little town, though infested with tourists (of which, yes, I know, we were two). I could see living there.

We stayed in a couple of B&Bs in Bath, and in the bathroom of one was an electrical fan which demanded that the electrical main be disconnected before servicing. I had no intention of servicing the fan, but I did get to wondering about the word "main". How was it related, if it were related, to the other various uses of "main" in English, particularly the ocean (the bounding main) and the "main" which means "primary", not to mention the phrase "by main force"?

I had always thought that that last one was related to French "main", "hand". It isn't. All the various uses of "main" in English have exactly the same root, to my considerable amazement.

The source is Indo-European "magh-", which means "might", as in "power". I'm not going to completely dissect it right now, because I have a bunch of books back home to which I'd like to refer, but I will get back to it next week. It is, though, pretty clear how all of the uses of "main" could be connected to the sense of "might", isn't it? So easy once you know how.