The clothes are styled with an emphasis on real and trompe l’oeil layering, with short-sleeved T-shirts over long-sleeved ones and paired with shorts atop trousers.

For fall, the runway models wore what looked like fancied-up do-rags or welder ear flaps under Amish-style hats. Some of it was pure runway hyperbole, but fundamentally, each piece is wearable and is meant to ring true to men — at least those who know what it means to make the walk from their home to the Metro on a cold winter morning carrying a heavy gym bag and dressed in an aesthetic state of limbo, somewhere between office attire and workout gear.

“It’s what we would actually wear and not look like we’re stepping out of a fashion shoot,” Osborne says. “It’s something we can wear from day to evening without looking FASHION — in all caps.”

The first men to embrace this look came from the world of music and sports. “I had dinner with [New York Giants wide receiver] Victor Cruz, and all he wanted to talk about is Public School,” says Eric Jennings, men’s fashion director for Saks Fifth Avenue. The style works for athletes, Jennings says, because “it’s casual, it’s comfortable, but it’s polished and dressy. These guys are under the microscope, and it can be appropriate for a lot of occasions.”

The sneakerheads were also early adopters; they came looking for something to pair with their fancy Givenchy, Saint Laurent and Lanvin high-tops. Other men followed, and retailers are convinced that more will come.

In Washington, the look can most quickly be spotted by looking down — at men’s shoes. Retro sneakers paired with work trousers and suits are the most obvious shift in style. That suit, by the way, is slim cut. And the pants are a little shorter than is traditional; they do not break over the shoes. In winter, men now pair technical parkas with their business suits, rather than standard wool overcoats. Messenger bags and backpacks have replaced briefcases.

Sportswear brands such as Vince and Theory have gently eased Washington men into this aesthetic. The Saint Laurent shop in Tysons Galleria stands ready to provide them with pricey sneakers and jeans. And as Saks Fifth Avenue increases the number of its stores carrying the full Public School collection, Chevy Chase is on Jennings’s expansion “wish list.”