The day dress, that symbol of '50s housewives and '70s secretaries, is being dusted off and embraced for work and play this summer, and it'll be flouncing into fall.

If luxury jeans-plus-flirty top was the uniform of choice for the first part of the decade, the dress — from the structured shirtdress to this season's floaty mini-frock — is reclaiming its spot at the front of closets everywhere.

For the 12 months ending in April, dress sales swelled an unprecedented 30.4% vs. the same period the year before, according to The NPD Group, a market research firm. The style shift toward shifts and sheaths is further evidence of the industry's continued sashay toward femininity, experts say.

Having left the androgynous '90s, we're now in denim withdrawal, says Jack Mascharka the designer behind Scharke. (Since it launched three seasons ago, the label's dress styles have increased from about four to at least a dozen.) "Jeans really homogenized women," says Mascharka. "The dress is being discovered as this amazing expression piece."

In 2007, women's jeans sales fell for the first time in five years, dropping 1.8%, according to The NPD Group.

Much like the suit, the dress is an easy way to get ready in the morning, says NPD chief industry analyst Marshal Cohen. "You don't have to go coordinate with three other pieces."

But unlike a suit, the dress is a canvas that's easily personalized. "You can belt them, accessorize them," throw on a jacket or pull on a cardigan, says Lucky fashion director Hope Greenberg. "It's the biggest fashion no-brainer."

And it has good legs. "The little dress phenomenon just keeps going and going," says Bridget Foley, executive editor of W and Women's Wear Daily. "They're fresh. They look great with a range of footwear."

As the frock fetish prances forward, Mascharka sees a focus on more fitted silhouettes and innovative sleeves. "We're finally moving out of the empire trend," he says — relief for "older women who aren't necessarily thrilled about baby doll dresses." Cohen forecasts skimpiness being swapped for "a little more coverage."

Flowy or form-fitting, it's all welcome news for clothing lines that have long focused on frocks, even when denim dominated. Dress sales at Jill Stuart are up more than 100% in the last year alone.

In the last 18 months, Shoshanna Gruss has seen her eponymous company, Shoshanna, grow nearly 50%. "For so long, the majority of the major department stores were so focused on T-shirts and denim they weren't even looking at lines like mine," says Gruss, whose collection is 95% dresses, from strapless solids to tunic-y prints. Frocks were "more for occasion dressing. Now contemporary floors are filled with dresses. People are buying less and less casual clothing."

It's about "wanting to be a little less overtly sexy," says Gruss, who dons dresses daily. "People just want to be prettier, a little more feminine." Gruss, who owns "thousands" of dresses, recently had new closets constructed, all at dress length. "The builders asked, 'Where are you going to put your pants and shirts?' I'm like, 'What pants and shirts?' "

There are practical considerations, too. Shorter women don't have to worry about getting anything hemmed. And with pants, "you gotta have a great butt all the time," says Gruss. "But with a nice full skirt, nobody really knows what that butt looks like. All you need are great calves and great shoes."

Early on in high school, Madeleine Kronovet's Manhattan closet was stacked with "probably 10 to 15" pairs of premium jeans. Now, the rising college sophomore is down to only one pair — and up to more than 25 dresses. (One of her two closets at school last year was largely devoted to them.) She sees her friends moving in a similar sartorial direction.

Kronovet, 19, wears frocks (she's partial these days to brief, billowy silhouettes) for going out as well as for her summer internship in New York Mayor Michael Bloomberg's office. "It's just a lot easier to go in my closet and put on a pretty dress and walk out the door," she says. Not to mention, dresses are ideal for "when it gets so hot."