Cabaret is as hard to define as it is to ignore these days. But as Peter Crawley learns, everyone has a hook to hang their feather boa on.

More than a century since it began, cabaret should have lost its lustre, or, at the very least, its controversy. And yet age has neither diminished it nor brought any great clarity. For starters, nobody can agree on a definition.

It can mean a particular venue, a lambent cafe or restaurant; it may involve a style of entertainment that encompasses the bawdy carry-on of a high-kicking chorus line, the ecstatic grief of the torch singer, the satirical snipes of a comedian or the feather boa of the chanteuse.

You could start with Christopher Isherwood's book, Goodbye to Berlin, or jump straight to the movie, Cabaret. The only real consensus is that cabaret is a performance.

To Karen Egan, cabaret is more demanding still - a tightrope between serious intent and a comic gambit - while the role of the diva is a playful feint. Towing a string of associations from a Weimarian hangover of decadence to the despair of Nazi suppression, the diva persona is glamorous, tragic, difficult and, in Egan's hands, pointedly ironic.

"If I seriously thought somebody considered me to be a diva, I would die," she laughs. "A large part of my show would be setting myself up to be this character with a rather enigmatic background." Egan's character - an international diva who is part-German, part-French, part-Turkish and now, for her show Absolute Cabaret, also part-Latin - is a vehicle for the music she hears in languages from German ("when it's sung it's very beautiful") to the marshmallow softness of The Girl from Ipanema sung in Portuguese: "The sound of that is just so beautiful to the ear, but also the actual words are so different. It's about the transience of beauty, it's not just about a tanned girl."

Egan is meticulous about her preparation, scrupulous about her foreign pronunciations, and serious about her music. In performance, though, she seems less serious about herself. "The best love songs are simple ones," she once told her audience, draped with a feather boa. "This is Ich bin von Kopf bis Fuss aus Liebe Eingestellt." It was an attractive comic fillip, and Egan let the German melt into the English verses of Falling in Love Again with Dietrichian aplomb.

Having served her time with the Nualas, Egan will never forsake comedy, but her cabaret also seeks a balance between light and shade. Still affected by her father's death, a huge fan of Dietrich, she says she cannot imagine doing a show that only contained comic material. She hears the beauty of the world and is compelled to share it with us.

That cosmopolitanism infuses the burgeoning Dublin cabaret scene, which, for the main part, is now a string of one-woman operations from its leading light Camille O'Sullivan (whom everybody now refers to solely as "Camille") to jazz singer Maria Tecce to French chanteuse Caroline Moreau or recent addition Derby Browne - a cottage industry of divas.

"We are drawing from other traditions," says Suzannah de Wrixon, who veers toward jazz singing. "Camille's work draws heavily from the French and German stuff and Karen is the same. But Karen would have quite a lot of her own material. I certainly delve into the American songbook. We've taken from others and made them our own. I'd hate to think we were stealing. It's an interpretive art. That's what makes it a cabaret; people go not only for what you do, but for how much of yourself you put in it. Everybody has a hook to hang their boa on."

Initially, the Boston-born singer Maria Tecce wasn't so sure."I didn't realise that what I was doing was cabaret until people started referring to me as a cabaret performer. I see cabaret as a marriage of different disciplines; it could be dance, music, text . . . but for me each song or number is a vignette, and the stories link together somehow."

A fluent and sincere jazz singer, Tecce began her performances from under the heavy camouflage of a character, the motor-mouth Virginia Devine, whom she long since abandoned. "In the beginning I felt that I had to feed the audience everything, and now I find that subtlety and simplicity are two things they appreciate. If the person onstage is truly inhabiting a story and believes what they're doing, audiences will want to come with you."

Her singing has changed, too. "I scat more than I ever did. To have a strong structural format but to also be able to take risks is what live performance is all about." This is not only a good working definition of jazz, but of cabaret as well.

And yet no one can coax the French singer Caroline Moreau into an affiliation with the artform, her own definition having been copper-fastened by experiences in the boisterous cellars of Montmartre. Cabaret, she outlines, is a type of venue in France where audiences eat and drink wine while various artists - men purporting to drink boiling oil, bearded ladies and so forth - attempt to build their career in 15-minute segments.

"The acts had to be extremely short and you had to show the best of yourself, and if the audience were not happy, they would throw tomatoes." The Dublin cabaret is different. For one thing, Moreau notes, "people don't throw tomatoes". It is also more theatrical. "Karen Egan and Camille, they're very good at that. They are extremely good with their bodies, at talking to the audience and involving them. It's not just singing the song; it's involving the whole actor's process."

This is why Moreau's performance, a combination of French chansons, Gypsy jazz and Argentinean tango, will never be advertised as cabaret. "It's kind of the blues that we are taking with us," she says. "Mixing our three blues creates something very deep and real about being homesick."

This artistic forlornness may ally Moreau to Dublin cabaret more than she recognises. "It's a lonely business," says de Wrixon. "Karen's doing it all by herself. Caroline has been doing it for a long time. And I started out with Camille. I know how hard she works. It's a long and difficult road." Yet for all the loneliness of the long-distance diva the scene is far more collegial than a history of old jokes might convey. (Example: How many divas does it take to change a light bulb? Answer: Three. One to change the light bulb, the others to stab her in the back.) Putting femininity centre stage, cabaret is markedly different from the majority of the theatre, music and comedy in the country, and even the world. It affords a performer huge control. "Divas are doing it for themselves," says de Wrixon.

On the strength of her hugely lauded Edinburgh Fringe Festival appearances, Camille won a role in Stephen Frears' recent film Mrs Henderson Presents. Tecce will release her second album, Torch Songs, next month. Moreau released the widely acclaimed Paris is Burning last year and continues to perform with Russian violinist Oleg Ponomarev. De Wrixon has a new show scheduled for April, once she has finished with yet another run of I, Keano, and Egan is nursing hopes for an album of original songs and the potential to tour. It's a hard slog, of course, done in many cases with neither financial nor managerial support, but the rewards are great. "As an artist working for yourself, designing, producing, directing, booking, doing the PR," lists Tecce, "being onstage is the gift that I get at the end of all that work."

So many layers of nostalgia have settled and caked on cabaret that it is hard to remember it as the avant garde haunt from which Futurism and Dada emerged; or the Charleston-dancing counter-culture of the 1920s; or even the subversive entertainment of Berlin in the 1930s or a crucible of political satire (and scandal) in 1960s London. It has fluttered between glamour and seediness, and scattered the seeds of its form. It deserves the credit for the enduring popularity of Jacques Brel and the Hip-Hop MC. It should take the blame for Rowan and Martin's Laugh-In and Def Comedy Jam.

"The vast majority of people don't know what to expect," says Karen Egan, who has adopted the work of Kurt Weill and Bertolt Brecht to accompany a striptease. "It could be singing, dancing, poetry, sketches, titillation, political satire, and an intimate setting, of course. It doesn't have to be all of those things, but I think it has to have some of them."

The potential alliances are innumerable. She happily traces melodic similarities between Peter Kreuder's Muzik-Muzik-Muzik and the theme to The Muppet Show. "I like to do those two songs together," she admits brightly, "with a sensational tap dance in between." That sure sounds like cabaret to me.

Karen Egan's new show Absolute Cabaret is in Whelan's, Wexford Street on Thursday. Caroline Moreau & Oleg Ponomarev are at the Pavilion Theatre, Dún Laoghaire, Feb 12 and Airfield, Dundrum, Feb 14. Camille O'Sullivan performs at the Olympia Theatre, Feb 26. Suzannah de Wrixon is at the Pavilion, Apr 21

Divas on divadom

Karen Egan "Yes, there are enough divas to start a union. In fact we have equity meetings every month. 'Diva hotline? Help! My shoes have broken!' "

Suzannah de Wrixon "I would not rate myself as a diva, although we do laugh about it. I always thought if I was to get together with someone else we'd call it Divalution. It's in jest, and yeah, it could be a dirty word too, because we're far from diva-like."

Maria Tecce "Historically 'diva' was a word of great respect and honour. That's the way I think of it. It was used in the same sentence as an artist who had reached a certain level of performance. Now it has been bastardised. It's used in the same sentence as someone who wants a bowl full of green M&Ms."

Caroline Moreau I would not define myself as a diva. Because people would then think it's about showing my legs and wearing wigs. Ah, no! Diva, in French, is a classical singer trained to [ she belts out a sudden shrill note]. So, I'm not.