Originally Posted by AutumnalTone
Ah, christ, please.
When the word "polyamory" was being coined, it was due to a need. The folks who coined it needed a term for a form of nonmonogamy for which there was no accurate term. Both swinging and open relationships had been in long use and had known meanings when referring to those forms of nonmonogamy.
Why were folks searching for a new term? Because what they needed to describe *is something different than what the terms "swinging" and "open" describe.* They needed a different term to describe a different way of doing nonmonogamy.
So, what do we know about the meaning of this new term, "polyamory?" We find that the it was coined specifically to describe a subset of nonmonogamy involving romantic relationships, and approach that the terms "swinging" and "open" do not describe.
As for the living language argument, I'll observe that the term qualifies as jargon and is not subject to the same sort of frippery that general language is. As technical terms in engineering or law or jewelrymaking or any of a multitude of fields show, jargon is held to different standards than general usage words so that the meaning is constant and useful. So, while "awful" may have some common connotations today that it didn't have 150 years ago, there are many terms that have the exact same connotations now as they did then. (I won't bother getting into how such slippage appears to happen primarily to adjectives....)
I would argue that, at least where marriage is concerned, you have to be "open" in order to be active swingers or polyamarous.