Forty years ago, this might have been a coming-out party for Cathy Hughes: a historied Georgetown manse, a Republican doyenne as hostess, a lush garden, 200 poised women accepting an initiate into the Washington societal stratosphere. Except Hughes probably never would have had a party like this 40 years ago.

Last night, however, a singular cultural nexus occurred. Hughes--founder of Radio One, a chain of 26 radio stations devoted to educating, entertaining and uplifting black audiences--was feted at the home of Pat Dixson--an old-guard presence who sells multimillion-dollar houses and raises money for the GOP.

The occasion--a party called "Divas Without Attitude"--was a celebration of Hughes's recent venture into the New York Stock Exchange. Radio One stock went public last month, making the 52-year-old Hughes the first black woman in the United States to own a publicly traded company, the party-givers said. The Lanham-based, $600 million radio chain has 26 stations from Boston to Atlanta to St. Louis, including WKYS-FM, WMMJ-FM and WOL-AM in Washington.

"You so rarely see parties that are so integrated in Washington," Hughes said of last night's unusual mix of guests--100 white women, 100 black women, with most of the handful of men in attendance wearing white jackets and serving chicken, collard greens and corn bread. "And tonight," Hughes added, "there are white women who have spent a lot of time thinking differently about the black women that they're meeting."

The overriding theme of the evening, however, was not color but gender, Hughes said. All the women at the party have faced similar gender-based obstacles.

"What we need," Hughes said, "is an old-girl network."

The crowd roared its approval.

The architecture of the event itself might be called a product of a newly formed old-girl network. Dixson and Hughes had not met until last night. But Hughes knew Jamie Foster Brown, publisher of Sister 2 Sister magazine, described as People for a black audience. And Brown knew Janet Donovan, another Georgetown social fixture, and she knew Dixson . . . and so the party.

Dixson lauded Hughes as "sharp and smart."

"She's the kind of woman that every woman wants to be right now," she said.

Del. Eleanor Holmes Norton dropped in, jumped into the middle of a crowd of women dancing to a Motown song, and boogied out. There was Debra Lee, the chief operating officer of Black Entertainment Television, and L. Marilyn Crawford, a vice president of Prudential. There was Cora Masters Barry (who did a rousing, non-ironic karaoke version of "My Guy"), lawyer Roscoe Dellums and Constance B. Newman, undersecretary of the Smithsonian Institution. This was definitely a party where you had to put the seat back down.

"The invitation said 'slacks and flats,' " said Vanesse Lloyd-Sgambati, a Philadelphia publicist. "Look around--do you see any? And any woman that does have them on is not a diva." Proving, as if it needed proof, that women dress not for men but for other women.

It became a real party around 9:30 when the cops showed up and asked Dixson to turn down the karaoke. And, as Donna Summer's "Bad Girls" thumped through the proper Georgetown neighborhood, a back yard full of women--professional, accomplished women--danced and danced. If only for a night, they were all once again just girls.

Staff writer Annie Groer contributed to this article.

CAPTION: One for the Women: Del. Eleanor Holmes Norton was among the 200 women gathering in Georgetown last night to honor radio mogul Cathy Hughes, who recently took her company public.

CAPTION: Radio mogul Cathy Hughes, the center of attention at last night's "Divas Without Attitude" gathering.