Here are the names of three products currently sold in stores and online: Pout Polish, Pout-à-Porter, Pout-o-matic. Here are three business names from around the United States: Kool Smiles, Smileworks, Smile Wide. And here's a question: What do those names tell you about what's being sold and to whom?

The answer may not come as a complete surprise, at least not if you read a lot of ads and magazines. But it isn't necessarily predictable, either.

The pout names come from the world of beauty journalism and makeup, where pout is now a popular substitute for "lips." When Kylie Jenner, the 17-year-old cast member of TV's "Keeping Up with the Kardashians," appeared in photos a couple of months ago with alarmingly enlarged lips, tabloid headlines took to citing "Kylie's famous pout" — even when she was smiling, not pouting. Young girls eager to emulate the look took the risky "Kylie Jenner Challenge," suctioning their lips on shot glasses, often with horrifically disfiguring results. Eventually Ms. Jenner admitted to having had lip injections. "Kylie Comes Clean About Her Super-Plump Pout" was the headline on E!Online.

The smile names come from the world of dentistry, a profession that until quite recently was better known for grimaces than for grins. Contemporary dental marketing focuses less on, say, the ravages of gum disease and more on brilliant, perfectly even teeth exposed by wide smiles; slogans like "Imagine Yourself with a New Smile" and "Keep Your Smile Healthy" are commonplace.

Used in this way, both pout and smile are examples of metonymy, a figure of speech in which a word or concept is substituted for a related one (for example, "Wall Street" for "financial markets"). But how did these particular words come to be used in these particular senses?

Pout was an English verb meaning "to puff out of the lips in displeasure" since at least the 1300s; the noun form (which is what I'm talking about here) emerged in the 1590s. The word's origins are uncertain, although it may be imitative of the shape your lips make while saying the word. (French has a related verb, bouder, which gave us boudoir — literally, a room for sulking.) For most of its history pout had generally negative connotations: petulant toddlers pout, as do sulky teens. Then, in 2002, a London weekly, News of the World, turned its attention to a British TV actress, Leslie Ash, who'd had silicone injections in her lips. The newspaper coined the term "trout pout" to describe the unfortunate results, and the catchy if catty rhyme caught on. (The label isn't quite scientifically accurate: trout don't have especially prominent mouths. Some other fish do, however. There's even a species, Trisopterus luscus, whose common name is "pouting.") In 2008, Ms. Ash appeared in a TV documentary about botched cosmetic surgery and talked to newspapers about "my trout pout hell."

Although "trout pout" was disparaging, the "pout" part took on a life of its own in judgment-free or even admiring contexts. For the last decade or so, beauty magazines have run features that counsel readers on how to plump your pout, perfect your pout, put power in your pout, make your pout pop, personalize your pout, and pump up your pout. (Alliteration, like rhyme, can be irresistible to headline writers.) The advent of selfies — self-portraits taken on mobile phones — has encouraged exaggerated pouting for the camera. (Another term for this look is duckface, which was coined for the 1994 film Four Weddings and a Funeral.) The shift to the positive end of the spectrum is reflected in some dictionaries: the OED and the online dictionary site include the concept of sexual attraction in their primary definitions of pout. (The first part of the OED's definition: "A protrusion of the lips, esp. as an expression of petulance or sulkiness.")

What makes a pout attractive? Fuller mouths are associated with youth; the lips tend to lose volume beginning around age 30. And pouting lips can look like they're preparing to be kissed. Most examples of the "attractive" sense of pout involve women, but men can pout enticingly, too, sucking in their cheeks to emphasize their cheekbones. (Think of Ben Stiller as Derek Zoolander.)

As for smile as a dental metonym, it represents a modern transformation of the image and function of dentistry. Of course, the word smile has been with us for a very long time: since about 1300. (It's related to Latin mirus, "wonderful"; the Old English word for smile, smearcian, comes down to us as the negatively tinged smirk.) But for generations, few people associated dental care with joy. Before fluoridated water and widespread dental-hygiene campaigns reduced the prevalence of tooth decay and gum disease, and before safe anesthesia made dental procedures bearable, dental advertising relied heavily on threats, scare tactics, and cajoling. "Painless" was the damned-with-faint-praise adjective most frequently used in conjunction with "dentistry." During World War II, saving teeth was a patriotic duty: "Dental care keeps him on the job" trumpeted a poster that depicted a sailor in the open-wide position. A 1972 poster seen in many dental offices warned "Teeth don't die a natural death. You kill them." (These and many other dentistry slogans from past decades are collected on an "Odontologia" Pinterest page.)

In the 1980s and 1990s, with cavities finally in retreat, dentists turned to cosmetic procedures to stay in business. Adult braces, veneers, and tooth-whitening (the last of which has increased "almost exponentially in the last 20 years," according to a 2013 report by the National Institutes of Health) are now viewed by many people as standard grooming practices. (Here again, celebrity role models have paved the way.) In this altered universe, going to the dentist is like going to the hair salon: something you do to look better and improve your self-esteem.

Another contributing factor to the smile surge may have been the international charity Smile Train, which was founded in 1999 to provide free surgery to children born with cleft lip or cleft palate. Though it doesn't provide dentistry services, Smile Train has successfully associated smile with "happy outcomes," and it uses the word relentlessly throughout its marketing: "Turn your shopping [on Amazon] into smiles," "Buy and sell used goods [on eBay] with a smile," "What has a smile done for you?"

The American Academy of Cosmetic Dentistry, which is in the dentistry business, appears to have taken careful notes. Its website,, has a Smile Zone (fun facts about smiles), a Smile Gallery (happy selfies), and a Smile IQ test as well as information about porcelain crowns ("this lifelike material creates a natural looking smile"), whitening ("a whiter, brighter smile"), bonding ("recreate your old smile"), and repairing chipped teeth ("restore your smile").

Of course, the smile in all those examples isn't actually what's being created, recreated, or restored: it's your teeth, and you can choose to display them, or not, any way you wish. You may, after you've received the bill for services rendered, decide that what's really called for is a scowl. Or even, if it comes to that, a pout.