To understand the place of a bellydancer in Egyptian society, there are two helpful things to know about. The Awalim, and the Zeffa.
The awalim were working in Egypt from the times of the Ottoman Empire. Their jobs were similar to a geisha's, they would sing, often improvising lyrics about their patrons and party guests, play music, and dance. Depending on what time frame we're talking about, they might only dance for the women's party.
This is a class of performer that one was traditionally born into, but one may also have be adopted into an awalim family, or simply hired into an osta's (head almah's) troupe. The family might perform together, thus offering a degree of protection for the performers. Dancers from this background might not disclose where they learned to dance, due to added stigma around the background, but we'll get to that.
Some osta opened dance halls where other awalim (and later bellydancers who had not grown up in awalim families) would dance and be discovered by the budding film industry. These might have been anything from a simple coffee house, to a supper club with an elaborate stage.
A zeffa is a "procession with noise", and it could be done for folks leaving on the haj, or a number of other reasons but, especially in dance circles, it refers to the zeffat al'arousa, the procession of the bride. This tradition is still a popular part of weddings, even if it is just a walk around the reception hall to start the party.
A traditional wedding zeffa included the women of the bride's family carrying long candles or frame drums, zagareeting as they walk with of the bride and groom. At the head of this is the bellydancer. Often with a lit candelabra called a shamadan balanced on her head to light the way.
Traditionally, a girl would live with her parents until she got married, at which point she would move in with her husband and his family and assume her marital duties, including starting a family. The zeffa has been part of the wedding celebration in Egypt and other parts of the Middle East for centuries. In ye olde times, this served the practical purpose of getting the bride and her belongings to her new home, and the social purpose of showing off her new status to the neighborhood. It also served an important psychological purpose for the bride herself: during this part of the celebration, the bride must make the transformation from the sheltered, virginal daughter to a wife and, if all goes well, soon-to-be mother.
That is a big change to make on a walk! Of course, she would have had a henna night and the council of her friends and family to help her prepare, but still. Sahra Kent, dance ethnologist from California, said of her research into the zeffa that
"Many people I interviewed believed the dancer, with her confidence in her femaleness, her sexuality, is one of the few things powerful enough to facilitate such a powerful and important transformation". (For a more in-depth and academic reading about the Egyptian Zeffa, subscribe to her email list and you'll get a free E-Book)
The dancer at the head of the zeffa would traditionally have been an almah (singular. Plural, awalim). Once the procession arrives at the reception, she would have the task of playfully teasing the bride and groom about their upcoming night. This clip, where Souad Hosney plays an almah, includes lines like "she's the violin and he's the oud, and together they will make beautiful music". This is for a movie, after all, so the lyrics are going to be quite a bit more tame than what you'd hear at a typical street wedding.
That is all good fun at a wedding, but can you imagine those songs outside the context of a new marriage? This is a woman who commands an entire orchestra of men, who can make a room full of people forget their troubles and be swept away by the party, who can transform a girl into a woman with a dance! That is a power that, while too important to the success of the marriage to do without, is also too potent to let loose on society.
This means dancers, like performers and artists in many cultures (including Euro-American cultures), are pushed to the edges of society. This can be liberating in some ways, and restrictive in others. While it means that a dancer doesn't need to play by many of the typical rules (at least not while on stage), it also means they can face stigma in their daily lives. Many of the great stars we admire from Egypt and Turkey have had to put up with a lot to continue their passion. At the same time, this role gives your dancing power to be reveled in.