(CNN) -- All Katherine McMillan wanted in a shoe was style and comfort without the frilly bows or flowers.
She's a working mother who tends to buy men's shirts in small sizes and prefers the kinds of casual shoes made for men -- desert boots, moccasins, chukkas. She'll take a pair of shoes or a jacket in olive green or navy blue over lavender or aqua any day.
"I think a lot of my friends would agree that we don't want to look like an Easter egg when we go out," said McMillan, who lives in Minneapolis, Minnesota. "I'm all for feeling like a girly-girl but there are ways to do it without being a French poodle."
Don't get her wrong, she likes high heels and dresses, but not in pink. So when she couldn't find a pair of shoes she liked, she decided to make her own.
Hers are desert boots, moccasins and chukkas made of leather and suede with a kelly green lining to distinguish them from what the guys wear. She launched her made-to-order collection in fall 2011 under the name Mrs. P. Hicks, a nod to Pierrepont Hicks, the successful menswear accessories brand she and her husband, Mark McMillan, created in 2009.
He runs the business while she is the creative force behind Pierrepont Hicks' collection of neckties, pocket squares and bow ties, which has earned a devoted cult following among menswear bloggers and the people who read them. For Mrs. P. Hicks, McMillan is designing for women who blur the line between masculine and feminine, who gravitate toward styles traditionally associated with men: flat shoes with wide lasts, unembellished blouses and button-up shirts, unstructured sweaters and blazers, jeans and pants lacking unnecessary studs, embroidery or whiskering.
"It's tomboy style, but that doesn't mean it's not feminine or sexy," McMillan said. "I think you feel sexy and stylish when you're wearing something you're comfortable in."
These looks have always been around, cycling in and out with the seasons, but the latest signs show they're more than just a momentary fad. Women are looking for shoes, shirts, even neckties that fit them better than their boyfriend's clothes. Also, brands are popping up to meet those demands, from the artisanal approach of Mrs. P. Hicks to mass-market retailers like Madewell and J. Crew, which have been widely credited with giving "tomboy" fashion broad appeal.
It's easy to forget the time before J. Crew or "boyfriend shirts," times when "nice girls" didn't leave home in pants. Katharine Hepburn and Diane Keaton were trailblazers, female fashion icons whose neckties and pants drew stares.
Modern style mavens Alexa Chung and Jenna Lyons show "tomboy chic" is more than a passing fashion, said Lizzie Garrett Mettler, creator of the popular "Tomboy Style" blog. Just as modern American women have won the right to vote and compete for the same jobs as men, it's nothing special for them to dress up in jeans or don a blazer.
A tomboy is more than a girl in boy's clothing, Mettler says in her blog; it's someone with an "inherent sense of confidence, rebelliousness and adventure." It's part style, part substance.
As brands continue to adapt traditionally masculine styles for the female form, "the new statement on tomboy style is that it's here to stay," said Mettler, author of the 2012 book "Tomboy Style: Beyond the Boundaries of Fashion."
Designer Sadie Beaudet was also drawn to menswear, but she didn't like the boxy fit on her body. She also didn't like how women's fashion was pulled from the racks one season and tossed a few months later, while menswear often had a timeless quality that never fell out of season.
With her fiance, she started Tradlands, a line of tailored women's shirts that incorporate masculine features, she said. It's a small collection of eight button-up shirts with a higher collar that doesn't necessarily lend itself to an exposed collarbone; the shirts have side gusset detail typically found in the workwear of the 1940s for reinforcement and brass snaps. All of their shirts are made in San Francisco, using denim and cotton sourced from the United States.
"We're trying to walk that line with a dash of feminism in the fit but clearly masculine in the details," she said.
Even the necktie is getting a feminine overhaul. What makes a lady tie? The fabric and the width, naturally, said Nashville designer Otis James.
His hand-stitched ties have earned him nods from publications like GQ and Garden and Gun. When the 29-year-old designer realized that many of his customers were women buying for their significant others, he decided to start creating products they might want for themselves.
"I'm hoping maybe they'll bring in more single women," James said, mostly joking, in an interview in his Marathon Village studio last month. "I think there's definitely a market for them."
Not everybody is comfortable with the word "tomboy." Some say the spirit of progressiveness has rendered the term archaic.
When Carmela Spinelli hears the word "tomboy," a particular look comes to mind: Strong, independent, rebellious. But the chairwoman of the fashion and accessories design department at the Savannah College of Art and Design said the description might need an update.
"To use a term that includes the word 'boy' to describe a state of independence and free-thinking for women seems kind of backward," Spinelli said. "The boundaries have changed. Women are strong and independent and have no sense of preciousness, so why would you use a term like tomboy to describe that?"
Perhaps it's because of the style's close ties to menswear. McMillan's Pierrepont Hicks is better-known, but Mrs. P. Hicks is her passion project. (Plus, she gets to keep the samples, she said.)
From the start, McMillan and her husband decided to keep their products made in the United States. That wasn't hard to do with neckties and pocket square, but it proved much more difficult for women's shoes, because so few manufacturers were equipped to do what she had dreamed up.
McMillan ultimately partnered with Maine-based mens' shoe maker Rancourt and Co., one of few shoemakers in the United States who specialize in classic men's styles similar to the ones she wanted. For her moccasins, she found another family-owned business in rural Minnesota.
With Mrs. P. Hicks approaching the two-year mark, McMillan said she has finally hit a groove and found a market.
"We even get orders from men now," she said. "They say they like the green interior."