Thank you for that! Although it explains the naming origin but not the word definition itself. So, I’ll go with the first english word that google decide to return 
Btw, my take on ARC has a more biblical dimension. It’s an ark that carries your precious music wherever you go. (and I can start the bad puns… ark, sea, c, see? ok ok I’ll stop now. sorries.)
We’re all contributing after-the-event rationales for the name of course since Roon staff have already said way up thread that it wasn’t really derived from anything but just sounded good, but as post rationalisations go I rather like that one. It doesn’t have to necessarily be biblical, another spin on your idea might be that it is short for “archive”, Roon ARC allows you to have your entire music ARChive accessible to you wherever you go.
Anal(Audiophile) Retentive Collaboration -ARC
Amber Rum and Coke
Alien Registration Card
Alcohilism Rehabilitation Center
ARChive
Anal Rectum Creme
…
Check please! Table one!
Aaaarrrrggggg Roon Crashed
Absolutely Really Cool 
Anarchic replay chatbot
Arch but the “h” gets upgraded from muted to invisible when using Caps Lock
It stands for All can’t Really Connect to it because of their ISP’s port limitations.
Ouch! I feel for those who are wrestling with the pig, in mud………
I guess I’m lucky having 4 ISPs to choose from
All Rumors Canceled
Aardvark Raspberry Conundrum
Absolutely Roontacular, Charles
Audio Research Corporation (ARC) founded 1970; 53 years ago.
I don’t think about using ARC in my car now that the novelty has worn off. We have a fantastic local jazz radio station. I’ve gone back to listening to it while I am out and about. I have heard the same sentiment from several others.
Perhaps if I commuted or was on travel. But I really don’t do either with any frequency.
In a similar fashion that Roon isn’t really known?
Seriously, you have to admit it was a poor naming choice.
What’s in a name? That which we call Roon
By any other name would smell as sweet.
I personally found the name ARC confusing. When I see the name ARC in an audio related context, my mind goes straight to room correction (interesting since I don’t use room correction).
While not as fancy and mysterious, they should have just named it Roon Mobile.
Before it was released, I was invited to participate in the beta testing. When I saw the name ARC, I thought it was room correction, so I signed up to be a tester. When it was later explained it was Roon mobile, I withdrew from being a tester.