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.

But not anymore. Gradually, and with relatively little fanfare, Verizon Wireless has deployed a nationwide cellular data network in the United States that blows away the fastest widely deployed networks in Europe, the so-called 3G networks that have been rolled out there to huge publicity. And Sprint is starting its own rollout of a similar speedy network based on the same technology Verizon uses.

That technology is called EV-DO, for Evolution-Data Only, or Evolution-Data Optimized. It is the first wireless technology deployed over a wide area that matches the speed of home broadband — at least the slower reaches of that wired service.

Unlike the most common form of wireless broadband, Wi-Fi, the new EV-DO service doesn’t rely on hot spots. It’s available all over a metro area, wherever there is cell phone service — even in a moving car.

Verizon has been rolling out the new service, city by city, over the past year or so, and it is now available in 61 major metropolitan areas and 65 airports across the country, according to the company. Because it’s based on a technology called CDMA, developed by the U.S. company Qualcomm and not widely used in Europe, EV-DO has given the U.S. an edge, even if only for a while.

You can get the service in two ways. First, you can buy a data-enabled smart phone, like the $600 Samsung SCH-i730, which can handle e-mail, instant messaging and Web access over EV-DO. Or you can buy a wireless EV-DO modem card for your laptop, like the $170 Kyocera KPC650, which allows all your Internet-oriented PC software to access the Web via EV-DO.

There are also different rates. Verizon has been charging $80 a month for an unlimited EV-DO data plan. But recently, it cut that price to $50 a month for people who already have a Verizon voice calling plan.

For those with mainstream phones that are mainly designed for voice calling but are EV-DO capable, Verizon offers a $15-a-month plan that mostly covers viewing short video clips on an EV-DO service called V Cast, but also offers unlimited, albeit much clumsier, Internet access.

How fast is EV-DO? Verizon is predicting average speeds of between 400 and 700 kilobits per second. That’s up to 10 times its previous fastest data speed, on an older network called 1X. In my tests, Verizon’s promise proved realistic, and I often topped 700 kbps.

To put those speeds in perspective, many wired DSL plans in American homes operate at speeds of 700 kbps or less, so EV-DO is in the same ballpark.

There are faster wired broadband connections available, from both DSL and cable modem providers. Many homes with cable modems have service that runs at 3 megabits a second, or four times faster than EV-DO. And some Wi-Fi hot spots may operate at faster speeds as well, though that depends a lot on how they are set up. But EV-DO is clearly a broadband service, at least by the American definition of the word “broadband.” (In Asia, they laugh at our definition. They think of broadband as being 20 to 50 megabits per second.)

So how does it compare with similar services in Europe? European cell phone companies offer better phones, better coverage, and better features and options, in general, than do their American counterparts. But strictly measured on data speed in widely employed networks, they’ve lost their edge. Their high-speed wireless 3G technology peaks at 384 kbps, which is less than the minimum speeds Verizon is promising. And such peaks in any system are rare outside the lab. (EV-DO peaks at 2.4 megabits a second.) Actual throughput with European 3G networks averages 250 to 300 kilobits a second.

In my tests of EV-DO with a laptop card, I averaged 585 kbps. And with the Samsung EV-DO phone, I was able to achieve EV-DO speeds of up to 534 kilobits per second.

The U.S. edge won’t last forever. New generations of the technology used in Europe, to be rolled out in the next few years, will top EV-DO. But there are faster successors in the EV-DO line of technology as well, so Verizon (and Sprint, America’s other big CDMA carrier) have their own future weapons. It’s a battle that should continue, as rival technologies steal the lead back and forth in their quest for dominance.

How does EV-DO compare with Wi-Fi? I love Wi-Fi to death and use it in my home and office, at airports and coffee shops. Even if you have an EV-DO modem in your laptop, I recommend having Wi-Fi as well, especially since it can be faster, and it is treated by Windows and the Mac operating system as a network. EV-DO isn’t quite as seamless on laptops: It gets treated like a really fast dial-up modem call, and the required software is a bit clunky.

But Wi-Fi is limited to places with hot spots or transmitters, at least until citywide deployments become a reality. And using it on the road often means exorbitant short-term fees to a variety of network operators, fees that could each top the $50 a month Verizon is charging its voice plan customers for unlimited use of EV-DO.

By contrast, with EV-DO, you pay one fee to one carrier and can use it anywhere in a city. In my tests, I was able to connect in restaurants, parking lots and even moving cars. And unlike Wi-Fi, with EV-DO, if you leave a coverage area, you don’t get cut off. Verizon merely slows down your connection to the pace of the 1X network.

EV-DO may even find a place in the home, replacing a wired DSL line. If all you use are laptops with EV-DO cards and your home is covered by EV-DO service, then you have all you need for broadband at home. And several companies are working on home wireless base stations that would work with an EV-DO laptop card.

The downsides of using EV-DO at home are that it’s much costlier than wired DSL or cable service, which typically runs $15 to $45 a month, and slower than any wired broadband but the slowest DSL plans. In fact, I believe one reason Verizon has priced it relatively high compared with wired broadband is to discourage home use, which might overload its network.

But for frequent travelers who rely heavily on EV-DO on the road, it may make better sense to just use it at home instead of buying wired broadband service as well, unless of course you have family members who do most of their surfing at home.

So, true, unbounded wireless broadband has arrived in the U.S., if you live in the right place and can afford it. Now you don’t have to take guff from Europeans anymore — at least about wireless networks.