Why We Need a New Definition of "PC" What is a PC? At first blush, it seems like a straightforward, uncontroversial question, not unlike "What is a bicycle?" But it's actually a surprisingly tough one to answer-and even if you've been using PCs for decades, you might have have trouble deciding what one is, and isn't, in 2012 and beyond. Research firm Canalys thinks it knows, and last month it announced that Apple was now the planet's leading maker of PCs. It achieved this distinction not by selling more Macs than ever-although it did-but because Canalys's definition of PC now includes something it calls "pads," such as the iPad, Kindle Fire and Nook Tablet. You and I are more likely to refer to them as tablets. Apple's iPad utterly dominates pad sales and outsells the Mac by three-to-one, which allowed the company to sail past HP for the top spot in PC sales. PHOTOS: A Brief History of the Computer Canalys says that pads accounted for 22 percent of PC sales in the fourth quarter of 2011, which means that more than three-quarters of the machines its survey covered were PCs of a more conventional sort. But with the tablet business booming and the traditional PC market appearing to max out, it's likely that a higher and higher percentage of the PCs that Canalys reports on in coming years will be unconventional ones. Of course, the fact that one research firm says that tablets are PCs doesn't mean that there's any consensus on the matter. When I asked my Twitter followers to define "PC" for me, I got dozens of cogent, disparate, often conflicting answers. One correspondent said it's "any personal computer based on an Intel microprocessor, or an Intel-compatible microprocessor." Another wrote that it's "a device that can run executable code including third-party software of some form in order to better my life." A third joked that a PC is "a tablet you can't carry." One simply maintained that a PC is "not a Mac." The traditionalists in the bunch tended to mention Microsoft, Intel or both companies in their definitions. That stance has always been up for vigorous debate: Even when I was editor of a magazine called PC World, I stubbornly insisted that Macs, as well as Windows computers, were PCs. Many of our readers, and some of my colleagues, disagreed just as passionately. "Is the Mac a PC?" is yesterday's debate. Today, it's more fun to squabble over whether the iPad and other tablets are PCs too. I say they are, a position that irritates certain people who dismiss the iPad as a superficial toy that's good only for consuming content, not creating it. But these naysayers are, well, wrong. If I sound snippy on this subject, it's in part because I wrote this column, and most of my recent pieces for TIME, on my iPad 2. MORE: How the iPad 2 Became My Favorite Computer The wheels will really come off the classic definition of PC later this year, when Microsoft releases Windows 8. Some Windows 8 PCs will look much like today's garden-variety desktops and notebooks, while others will compete directly with the iPad. If a Windows 8 device has a physical keyboard and mouse, you may be able to ignore them and use it through touch alone; if it's a tablet, you may be able to snap on a keyboard and use it like a laptop. There will be models that use Intel-compatible chips, like all current Windows machines, and ones based on processors that also power smartphones and tablets. In short, Apple, Microsoft and other companies are stretching the PC more than ever. Still, it's worth trying to formulate a new definition-one that will hold up no matter what happens in the world of personal technology. Would you mind if I took a stab at it? A PC runs apps. The owner gets to define the device's capabilities by installing software on it-and, these days, by using it with Web-based services. It's a general-purpose device. You can use one to write a novel, balance a checkbook, listen to a symphony, design a jumbo jet or pretend you're Batman. True, most people don't use a single PC for quite so dizzying an array of tasks-but they could. It's designed principally for use by one person at a time. That's where the "personal" in "personal computer" comes in. It's a computer for you, which was a pretty radical notion when the PC first got going in the mid-1970s, and still a liberating one. It can be of any size. Which means that smartphones are PCs, since they run general-purpose software and are generally used by one person. In an era of products such as Samsung's Galaxy Note, which is as much tablet as phone, I see no reason to declare that something isn't a PC simply because it fits (just barely) into a pocket. My definition of PC is intentionally flexible, but it's not arbitrary. I don't consider the PlayStation 3, Wii or Xbox 360 to be PCs, despite their obvious PC-like qualities; they're focused on games and other entertainment, and are frequently used by multiple people at one time. For the same reason, even the smartest of smart TVs don't strike me as being PCs. If you disagree with my definition, I'm neither startled nor offended. Over the next few years, consumers and businesses will get to decide, collectively, which fresh takes on this old idea make sense, and which don't. As one of my Twitter followers put it, "Whatever someone buys when they want a computer is a PC." That may be vague and non-committal-but it's also the only definition that's always been true, and always will be. MORE: Looking Forward to 2012: Credible iPad Threats McCracken blogs about personal technology at Technologizer, which he founded in 2008 after nearly two decades as a tech journalist; on Twitter, he's @harrymccracken. His column, also called Technologizer, appears every Thursday on TIME.com.