In 1955, Ford hired the poet Marianne Moore to suggest names for a new car still on the drawing board. The carmaker had big plans for the vehicle, and it asked Moore for words that would convey speed, sophistication and state-of-the-art design to prospective buyers. Proving perhaps that poets think years ahead of their time, Moore came up with the names Civique and Diamant, among others.

The company ended up calling the car the Edsel, after Henry Ford's son. You know what happened to the Edsel. Who knows what happened to the guys in rewrite?

Nowadays, naming is serious-and often secret-business. It has become the province of copywriters, focus groups, marketing executives and professional branding specialists. Some car companies simply won't talk about how they settle on names for their products. But more and more automakers have eschewed words entirely and resorted to weird combinations of letters and numbers to identify the models in their lineup. In fact, about one-third of the 200 best-selling cars and SUVs on the U.S. market now sport letters, numbers or some combination rather than names. That's more than twice as many as 20 years ago.

Usually, there's a method behind the apparent alphanumeric madness. And knowing the method can often reveal something about the size, personality and performance of the model to which the letters and numbers are attached.

Alphabet Soup

Take Cadillac, for example. A few years ago, General Motors' luxury brand began replacing traditional monikers such as DeVille and Seville with DTS, STS and other three-letter combinations. "Of course, the old names had a lot of equity in the marketplace, so it was a risk to some degree," says David Caldwell of Cadillac. "But we wanted to communicate that Cadillac was making a lot of changes for the 21st century, including more dramatic styling and surprising performance. We thought that the best way to signal that was by changing the names."

The idea of using letters came from the Seville. Cadillac had always offered a trim level called STS, an informal designation for "Seville touring sedan." Customers began dropping the model name and referring to the car simply as the STS. When Cadillac replaced the Seville with a similar-size sedan, they kept STS as the "Seville-size touring sedan."

Cadillac's other letter designations follow the same logic, with CTS (Catera-size touring sedan, referring to the car that it replaced) and DTS (DeVille-size touring sedan). In other words, the first letter of the designations indicates relative size. The last two letters offer a coded clue about the personality of the vehicle-except when they don't. For example, Cadillac offers a crossover vehicle built off the STS platform and calls it the SRX. The X represents crossover, and the R represents - well, bubkes. "It doesn't stand for anything," explains Caldwell. "We should've called it the STX, but that just didn't roll off the tongue as well as SRX." He adds with a smile, "We reserve the right to break our rules whenever we want to."

How the Imports Do It

In using letters instead of words to identify its models, Cadillac followed a long tradition established by imported competitors such as BMW, Mercedes-Benz and Lexus. Most European and Japanese companies take a slightly more systematic approach, however. Their alphanumeric designations reveal more, too.

For instance, Lexus uses letters to indicate relative size and numbers to denote the engine size in liters. Think of the ES 330 as the "executive sedan" with a 3.3-liter engine and the LS 430 as the "luxury sedan" with a 4.3-liter. The carmaker borrowed from gran turismo (the original long-distance auto races, not the video games) to come up with its gran sedan (GS).An international sedan (IS)-not coincidentally, a big seller in Europe-and a sport coupe (SC) complete the passenger car lineup. The SUVs follow a similar pattern. The RX signals a "recreational crossover" and LX, "luxury crossover."

BMW and Mercedes have used similar grammar for years. For BMW, the first digit represents the class-3, 5, 6 or 7 Series, in increasing order of size. The German carmaker reserves odd-numbered series for sedans and even-numbered ones for coupes. The last two digits indicate the engine size in deciliters-or, at least, they usually do. In just one example of understatement, the BMW 325i has a 3-liter engine, not a 2.5-liter as its designation would imply. Letters at the end denote other specifics-i for injection (a vestige of the era when you needed to distinguish between carburetors and new-fangled fuel injectors), x for all-wheel drive, C for coupe, L for long wheelbase, to name a few.

Mercedes, of course, famously uses letters to designate size class and numbers to designate the engine size in centiliters. Like BMW, Mercedes' designations occasionally overstate or understate the engine size a bit. With both German carmakers, you can think of the first number or letters as indicating the "model" and the subsequent numbers as indicating the trim level, since other equipment often varies along with the engines.

Then again, some carmakers have no system-or none that they will admit to. An Acura spokesperson, for example, claims that its RL, TL, RSX and MDX designations don't stand for anything at all-except for NSX, which stood for "new sports car experimental."

Code Worthy of Da Vinci

All these coded letters and numbers might seem like some strange automotive equivalent of The Da Vinci Code, where every combination has a secret or not-sosecret meaning. But why are so many carmakers ignoring plain, old-fashioned names? Don't words conjure up marketable images better than letters and numbers?

Industry experts offer several explanations for the alphanumeric trend. For one thing, unlike words, letters and numbers resist mistranslation in the global marketplace. Who can forget Chevrolet's gaffe when it tried to sell its Nova overseas in the '70s? Apparently, no one noticed that the name translated to "won't go" in Spanish. Fiat had the same problem when it tried to market its Rustica in Great Britain and found that the car had corrosion problems in the northern climate.

For another thing, carmakers encounter fewer trademark infringement problems with letters and numbers than they do with names. That didn't stop Nissan's upscale Infiniti brand from filing a lawsuit against Audi over use of the letter Q to designate a line of SUVs recently. But on the whole BMW doesn't care that Mazda also has models known as 3 and 5.

Most of all, though, dreary alphanumeric designations focus a consumer's attention on the brand's nameplate, not the model. And in marketing, brand identification has become the Holy Grail. That explains why nearly all luxury carmakers-even Lincoln and Cadillac-have begun to adopt them.

Rest in peace, Miss Moore.