And like the technologies themselves, digital jargon changes and expands all the time. Just when you thought you’d mastered stuff like RAM (computer memory) and GSM (the cellphone technology invented in Europe), new terms pop up like weeds on your lawn.

So here’s a quick and dirty glossary designed to make holiday shopping for the latest tech products feel less like taking the SATs.

Computers
Some of the newest terminology to know when you’re shopping for a computer, whether it be a Windows PC or an Apple Macintosh, involves the processor, the chip that’s the brain of the box. Until recently, most consumer computers had a single processor. Now it’s common to find them with so-called dual cores, which in effect means two processors packaged into one chip. Two cores won’t make your word processing or email go any faster, but they do potentially give you more horsepower for such heavy-duty tasks as gaming or video editing. I say “potentially,” because to make the most of a dual-core processor, you need software that sends some work to each core, and most programs are not yet designed to do that.

The labeling of these new processors is also confusing. Intel called its first consumer laptop dual-core chip the “Core Duo”; now there’s a second generation known as the “Core 2 Duo.” (In techland, apparently, the “2 Duo” moniker is assumed to be crystal clear.) And there are still some single-core Intel processors, dubbed “Core Solo.”

For laptops in general, one of the latest terms you’ll encounter is “ExpressCard,” which refers to the new version of that slot on the side of the machine into which you can pop a wireless receiver or some other add-on. For years these slots have adhered to a standard called “PC Card,” but the latest laptops are showing up with slots that follow the new ExpressCard standard. Worse yet for confused consumers, it comes in two flavors: a narrower one called ExpressCard/34, and a wider one called ExpressCard/54. And naturally, neither can accept cards designed for the older, PC Card standard.

Cellphones
One hardly knows where to begin when talking about cellphone jargon. But an obvious source of confusion is the baffling nomenclature being given to the various new high-speed cellphone networks that can transmit a wide assortment of material — music, video clips and web sites — to phones at speeds rivaling home broadband.

If you’re shopping for a phone at Verizon or Sprint, the high-speed capability is called “EVDO” or “EV-DO” (which stands for Evolution Data Only or Evolution Data Optimized). At Cingular, it’s known as “HSDPA” (for High-Speed Downlink Packet Access).

Since T-Mobile doesn’t have a network in this speed class, salespeople there will brag instead about “EDGE” (Enhanced Data Rates for Global Evolution), which, despite its aspirational name, is a much slower technology.

TV
Buying a television used to be simple. No more. There’s a whole new vocabulary for digital TV shopping. It’s too expansive to cover completely in this space, but here are a few select terms.

In addition to the familiar plasma and LCD (liquid crystal display) sets, which have an expensive digital panel at the front, there’s now a third type of screen, called a “microdisplay.” This is actually a rear-projection television, although much skinnier than the old behemoths. There are three main microdisplay types. Each uses a different sort of very small digital circuit in the rear of the set to generate the picture, which is then projected onto the large screen at the front. And naturally, each has its own jargony name. The first, called “DLP” (digital light processing), uses a special chip loaded with minuscule mirrors. The second, confusingly called “LCD,” uses a tiny LCD chip. The third, “LCoS” (liquid crystal on silicon), is sort of a hybrid of the other two, in that it uses both liquid crystals and mirrors.

And don’t forget the digital video recorder — the now almost mandatory add-on used to record and save programs on hard disks inside cable and satellite receivers or inside a stand-alone unit — which unfortunately goes by two names. Sometimes it’s called a “DVR” (digital video recorder) and sometimes a “PVR” (personal video recorder), but really, they’re the same thing. You might even hear the technology referred to as “TiVo,” which is actually the best-known brand of digital video recorder. Think of TiVo as the Kleenex of DVRs — its name is sometimes used as a generic term for the whole category.

Wireless
Wi-Fi wireless networks are now pretty familiar. Many people even know they come in two main speeds, designated by letters. The “b” variety, which was the first version to gain public acceptance, was succeeded by the “g” variety, which is faster and backwards-compatible with “b.”

Nice and simple, right? Not for long. Chaos has come to the Wi-Fi world in the form of a new standard,”n,” which is supposedly even faster than “g” and, more important, offers longer range. The problem is, the engineering committee that sets such standards has been taking forever to certify “n,” so companies have begun selling Wi-Fi gear that purports to use the “n” standard in some form but may not be compatible with it when it finally emerges. Last year there were “pre-n” products, which used some parts of the emerging standard; this year there are “draft-n” products, based on a draft of the proposed “n” standard. Stay tuned for the real thing.

But the most important Wi-Fi term of the moment is “MIMO,” short for multiple-input multiple-output. This is a technique that can greatly improve range and speed by capturing formerly stray parts of a wireless signal and merging them. It is expected to be a key component of the “n” standard, but is already in some “g” products, as well as in the “pre-n” and “draft-n” products.

Broadband
There are two main types of high-speed Internet service: DSL (digital subscriber line) is sold by phone companies, while cable modem service is sold by cable companies. Most people know these terms.

But now there’s a third type, called “fiber optic,” being sold in some parts of the country. This technology uses glass fibers, lit up by a laser and connected directly to your home. (Some other systems use fiber under the street, but not running right up to the house.) The best-known brand of fiber-to-the-home broadband service is Verizon’s “FiOS,” which can deliver TV channels as well as the Internet.

All broadband service providers boast about their speed, and they tend to do so in techie jargon. Slower broadband is measured in kilobits per second, abbreviated as “kbps.” Faster speeds are clocked as megabits per second, or “mbps.” (Note that these terms end in bit, not byte. The latter ending is normally used as a measure of storage capacity, not speed.) One megabit equals 1,000 kilobits. So a DSL line that tops out at 768 kilobits per second, for example, isn’t nearly as fast as one that registers three megabits per second.

Music
Almost everybody knows that MP3 (MPEG-1 Audio Layer 3) is the most common format for digital music files. But what is AAC? And how about WMA?

All of the above are compressed formats, meaning they take a song that would occupy lots of space on a disk and squeeze it down to a fraction of its original size while trying to preserve the sound. AAC (Advanced Audio Coding) is an industry-standard music-compression format favored by Apple, while WMA (Windows Media Audio) is a proprietary music-compression format that is owned and used by Microsoft. Which of the three you prefer depends on your taste.

Both AAC and WMA are available in two versions. One is an “open” version, which gets created when consumers convert their CDs into these digital formats, and imposes no restrictions on usage. The second is an encrypted, or copy-protected, version, which includes code that restricts how often and under what circumstances the song can be played or copied. Songs sold at Apple’s iTunes Music Store are in the encrypted version of AAC, while songs sold by music services that use Microsoft software are sold in the encrypted version of WMA, meaning there are limits to what you can do with these files.

And then this year everything changed. Apple Computer, the maker of the Mac, switched to the same Intel-made processors for which Windows was designed. The new Intel-powered Macs, which began shipping in January, still come with Apple’s own operating system, Mac OS X, which is more modern and more secure than Windows XP. But these Macs can now easily run Windows too, and they run it as fast as standard Windows-equipped PCs.

Why does this matter? It means that you can switch from Windows to the Mac and still use the one or two Windows programs you require that have no Mac equivalent.

Among the Mac models that can perform this feat are the iMac and Mac Mini desktop computers and the MacBook and MacBook Pro laptops. Apple’s most powerful model, the PowerMac tower, is likely to be converted to the Intel chips by the end of the year, after which it, too, will be Windows-capable.

There are two options for running Windows on the Mac. They take different approaches, but in my tests, both have proved to be fast, stable and widely compatible with Windows software. One, from Apple itself, is free. The second, from a small Virginia company called Parallels, costs $79. But each carries an additional cost: You have to supply and install your own copy of Windows, which can run $200 or $300, depending on which version you choose.

The Apple system, Boot Camp, uses a technique called Dual-Boot. It splits your Mac’s hard disk into two sections, or partitions — one for the Mac operating system and all its programs and files, and one for Windows XP and all its programs and files. You can start, or “boot up,” the Mac in either operating system, but you can’t run both simultaneously. To switch between a Mac program and a Windows program, you have to reboot the computer.

The Parallels system, called Parallels Desktop for Mac, uses a technique called Virtualization. It creates a virtual Windows computer inside a window within the Mac operating system. Parallels runs Windows a tad more slowly than Apple’s Boot Camp, but allows you to run both operating systems, and compatible software, simultaneously. You can switch rapidly between the two environments without rebooting. I’m writing this paragraph on a MacBook Pro laptop, but I’m not using any Mac software to do so. Instead, I’m using the Windows version of Microsoft Word, which runs inside Parallels Desktop.

For this paragraph, I’ve switched back to the Mac side of the computer and am using the Mac version of Word. And I copied the previous paragraph from the Windows side and pasted it into the Mac document. It was fast and flawless.

Each approach has its strengths as well as weaknesses.

Apple’s Boot Camp turns the Mac into a true, no-compromises Windows PC-just like a Dell or Hewlett-Packard computer. When you boot up the Mac in Windows, no trace of the Mac operating system is running; Windows has all the hardware and all the memory to itself. In my tests, Macs running Windows under Boot Camp were wicked fast and handled every single program I tried, including Microsoft Office for Windows, the Internet Explorer Web browser and various games. The downside is that pesky need to reboot when switching operating systems.

Parallels Desktop is much faster than the old software for running Windows on pre-Intel Macs, a Microsoft product called Virtual PC. That’s because Parallels makes use of special virtualization features built into the Intel chips. And it has the great advantage of running Windows applications at the same time you are running your Mac programs. But while quite fast, Parallels can’t match the speed of Windows running under Boot Camp, because it must share hardware and memory with the Mac operating system. Also, Parallels won’t work with certain high-end Windows games, and it can have trouble recognizing some USB drives and CDs. In my own tests, Parallels did handle everything I threw at it, but I introduced only simple games. Everything ran as fast as it would on an average Windows PC, though not as fast as the programs ran under Boot Camp.

Because Windows is much less secure than Mac OS X, when you run Windows on a Mac, you have to take the same precautions you would with a standard Windows PC. That means you need to install and run both antivirus and antispyware software that is generally not needed under the Mac OS.

Apple’s approach is more secure than Parallels’s in this regard — with Apple’s Boot Camp, Windows can’t see or access your Mac folders or files. That means any malicious software running in Windows can’t erase or damage your Mac files. Parallels, on the other hand, optionally allows you to share folders between the two operating systems; if you enable this feature, you could give a malicious Windows program an opening to damage or spy on the files on the Mac side.

Installing both programs is fairly easy, but it’s a multistep process. With Apple’s system, you first download and install Boot Camp. Then, using Boot Camp, you divide your hard disk into Mac and Windows partitions. Next you create a CD to be used later, under Windows, to install software “drivers” that Windows will need to control all aspects of the Mac’s hardware. Then you install Windows. Finally, you install the CD you created.

Note that Boot Camp requires a full retail version of Windows XP, called “SP2.” You can’t use any other version of Windows, and you can’t use an upgrade edition, which requires an earlier version of Windows to be present on the machine.

Parallels allows you to install any version of Windows, even a very old one. But if you use Windows XP, you will in most cases also need a full, retail version, not an upgrade package. You first must buy and install the Parallels program, which creates an empty “virtual machine.” Then you install your copy of Windows inside Parallels. Finally, to enable certain key features, you have to install a program called Parallels Tools, which is included.

This all sounds harder than it is. In each case, the whole process took me about an hour and required no technical skill.

And it’s worth the effort. Boot Camp and Parallels have turned the Intel-based Macintosh into the only computer that can run nearly every popular software program, whether it was written for Windows or the Mac. On the same computer you can edit photos in Apple’s iPhoto program and check your e-mail in Microsoft’s Outlook — simultaneously, if you choose Parallels. Now, that’s progress.

Starting in January, six months earlier than promised, Apple began switching the Mac to the very latest Intel processors-allowing higher speeds at lower temperatures compared with the previous IBM chips. Apple’s sleek, slim computers can run faster without bulking up for extra fans or heat-dispersion space.

That change, in turn, enabled Apple to stun the world in April when it announced a free utility that permits the Intel-based Macs to run Windows as a complement to the Mac operating system. With this new software, called Boot Camp, a Mac user can start up the computer either as a Mac or as a Windows machine. That means people who resisted switching to the Mac because they need to run one or two programs available only in Windows can now convert without hesitation.

America’s slimmest brand-name desktop, the dazzling white iMac, now runs faster with Intel chips yet retains its slender form. So does the thin, aluminum-clad 15-inch MacBook Pro laptop, a renamed version of the PowerBook. Like its Mac siblings, the tiny Mac Mini desktop now includes an Intel processor that incorporates two “cores,” the equivalent of two processors in one.

These Intel models are Macs through and through because they still run Apple’s Mac OS X operating system, Tiger — which is so far ahead of Windows that it already contains the key features Microsoft is promising for its much-delayed new version of Windows, Vista, due in January.

But now Macs can run Windows as well. Apple’s other models should be converted to Intel by late 2006. They include the 17-inch-screen version of the MacBook Pro laptop, the thinnest and lightest portable available; the entry-level MacBook laptop, formerly called the iBook; and the top-of-the-line PowerMac towers.

The new Mac lineup doesn’t include some categories of computers offered by the likes of Dell and HP. For instance, Apple lacks an ultralight laptop like the 2.5- to 3.5-pound Windows models from Sony and Toshiba. It doesn’t offer gaming-specific desktop towers or big laptops, like those from Alienware and Dell. And it doesn’t offer models with built-in TV tuners and TiVo-like digital video recorders, like those available from most PC makers.

Also, while Macs now use standard ports and connectors, which can accommodate most any printer or scanner, they omit a couple of common features found on many Windows machines. They’re not equipped with readers for camera memory cards, and the laptops don’t have built-in receivers for the new, high-speed cell phone data networks. You can add both of these features as external add-ons, at extra cost.

On the other hand, Macs running the OS X operating system aren’t susceptible to the many thousands of viruses and spyware programs that plague Windows computers; most Mac users don’t bother to run antivirus and antispyware software.

Then there’s price. Years ago Macs cost much more than Windows PCs. That’s no longer true. The iMac is priced comparably to identically equipped Windows machines, though no similar Windows desktop is as slim. Mac laptops can run a few hundred dollars more than Windows models, though comparable Windows laptops tend to be thicker and heavier, with lower-quality screens.

But Apple has no offerings cheaper than its $599 base Mac Mini, which lacks a keyboard, monitor and mouse. It doesn’t play in the market’s bargain-basement segment, where Dell, HP and others have stripped-down models that sell for under $400.

Here’s a quick guide to the fresh Mac models, and to their new ability to run Windows.

DESKTOPS

The iMac. This is Apple’s flagship product, its main consumer desktop and, in my view, the best available consumer desktop. At first glance, it looks like just a sexy, white, flat-panel monitor. But there’s a powerful computer packed behind the screen, which can also run Windows. The iMac also has a built-in video and still camera, plus a special operating mode called Front Row that allows you to play music, videos, DVDs and photo slide shows from across a room, using an included remote control. The iMac starts at $1,299, complete with a built-in flat-panel screen.

The Mac Mini. The smallest desktop computer I’ve ever tested, at 6.5 inches square and 2 inches high. Yet it’s a full-fledged Mac, complete with the latest Intel chips, that can also run Windows. Starting at $599, the Mini includes Front Row with remote control and is often bought for connecting to a TV as a media hub.

The Power Mac. This is a heavy-duty tower, favored by graphic artists, musical composers, video producers and scientists. It has yet to be upgraded to Intel processors, but currently can be ordered with as many as four IBM G5 cores. For most consumers, it’s overkill. It starts at $1,999, without a monitor.

LAPTOPS

The MacBook Pro. Apple’s top laptop, a renamed, reengineered version of its famous PowerBook that looks and works pretty much the same-only faster. Though currently available only with a 15-inch screen, for $1,999, a 17-inch model may roll out. It’s not clear if the 12-inch PowerBook, which remains on sale at $1,499, will also be replaced.

The main difference between MacBook Pros and PowerBooks? The former use the new Intel processors, have built-in video cameras, and feature Front Row and the remote control. Oh, and they can run Windows. The MacBook.This is the rumored name for a new entry-level Intel-based laptop that will soon replace the iBook. It should be much faster and also be able to run Windows. Meanwhile, the iBook remains on sale, starting at $999. It uses the older IBM G4 processor.

WINDOWS ON A MAC

The new Intel-based Macs can run Windows via Boot Camp, a free Apple utility that overcomes some subtle hardware differences between the Intel-based Macs and standard Windows computers.

After you run Boot Camp, you simply buy a copy of Windows XP (Apple won’t sell or support Windows) and install it as you would on any regular Windows computer. You must use a full, nonupgrade copy of Windows that includes the update Microsoft calls “SP2.” These versions of Windows cost $200 to $300.

Once Windows is installed on a Mac, each time you start up you can choose whether to run the Mac OS or Windows. Only one operating system can be used at a time, and each controls its own walled-off section of the Mac’s hard disk.

In my tests, an Intel iMac running Windows performed like a fast, normal Windows computer and ran every Windows program and hardware device I threw at it.

Apple isn’t abandoning its operating system or switching to Windows. It’s making it easy to run Windows on a Mac in hopes of tempting potential switchers who would use the Mac OS most of the time, but need to shift to Windows periodically to run programs that don’t have Mac equivalents.

Macs aren’t for everyone. But they are superior computers, and with the new Intel chips and Windows capability, they are more attractive than ever.