Hardware maker Xi3 is pushing back against Valve's attempts to distance itself from Xi3's $1,000 Piston PC-in-a-console, setting off a debate about what, precisely, is meant by the heavily bandied-about term "Steam Box."

When Xi3 first unveiled the Piston (then simply called a "modular computer chassis") at CES in January, the company trumpeted a monetary investment from Valve and highlighted how the system was designed to play Steam games on high-definition TVs and large monitors using Steam's Big Picture mode. But soon after Xi3 started taking preorders for the Piston over the weekend, Valve put out a statement saying that it "began some exploratory work with Xi3 last year, but currently has no involvement in any product of theirs."

Xi3 came out with its own statement today reaffirming its relationship with Valve, saying that the Piston was a product Valve specifically asked the company to build. While the statement seems to acknowledge that Valve is not currently directly involved with Piston development, Xi3 clarified that "just because Valve may not 'currently' have any 'involvement with any product of ours doesn't mean that such involvement won't exist in the future."

More importantly, though, Xi3 noted that the Piston will be able to run Steam games "regardless of what our relationship is or isn't with Valve." Moreover, "Piston will also support a raft of other Internet-based gaming and entertainment platforms, which is more than what Valve apparently has planned for its official Steam Box.

"In this way, the Piston Console could be perceived as something more than just a Steam Box..." the statement continues.

The whole back-and-forth brings up an important question: what exactly does it mean to be a "Steam Box?" In a sense, any computer that can run Steam could be considered a Steam Box. That's not a very useful characterization, though, since by that standard practically every Windows, Mac, and Linux PC qualifies.

In general, the "Steam Box" concept as Valve has discussed it connotes hardware designed for comfortable use in the living room through Steam's Big Picture interface. This usually means a small, simple, console-style form factor, rather than a big, boxy, energy-hogging PC tower sitting next to your entertainment center. It also means a focus on wireless handheld controllers rather than a keyboard and mouse.

By this definition, the small, power-sipping Piston could definitely be considered a Steam Box. But that doesn't mean it should be confused for the Steam Box, which is the game-playing hardware Valve is currently working on internally (the company seems to be preparing to release it as a prototype in the coming months). Valve has been incredibly cagey about precisely what it has planned for this "official" Steam Box architecture, but it will probably set the standard for what will be expected from third-party hardware makers jumping on the Steam Box bandwagon.

And make no mistake, Valve isn't opposed to other hardware makers creating their own Steam Boxes. Cofounder Gabe Newell has said many times that he expects a variety of Steam Boxes from a variety of vendors at a variety of points on the price and hardware spectrum. It's unclear how directly Valve would be involved in these "unofficial" Steam boxes, but it's not out of the question that the company could create some sort of certification program that gives an official "Steam Box" designation to machines that meet certain performance and feature standards. In the absence of such a program, though, the "Steam Box" name is kind of up for grabs for the time being.

Then there's the OS. The official Steam Box developed by Valve will probably be based on Linux to lower costs and to reflect Newell's growing dissatisfaction with Windows. But the selection of Linux games on Steam is not very robust at the moment, to say the least, which could be quite the limiting factor for the official hardware. Xi3, for its part, has clarified that the Piston will ship with a Windows operating system at its core, so it can support the platform "where the vast bulk of game software and computer gamers are today."

There's also the implication that the Piston is somehow better than Valve's official box because it will be able to run non-Steam games and apps. Here, Xi3 probably goes a little too far. Newell has publicly talked about the benefits of Steam Box's open PC architecture, including the ability to run things like Facebook, Twitter, and iTunes "without having to worry, 'Oh my god, how are we going to get that application running on our TV.'" Just because a Steam Box can run Steam, in other words, doesn't mean it can only run Steam.

So where does all this leave us? We can't really put it better than Xi3 did in wrapping up its latest statement. "In closing, what Valve does or doesn't do with its Steam Box will be up to them. So Gabe, it's up to you. The ball is in your court." Until Valve picks up that ball, though, it's probably safe to call the Piston a Steam Box for the time being.