That naughty "f" word

These days "contemporary acoustic music" is all the rage - just don't call it folk

Adem Ilhan bristles audibly - if such a thing is possible - when I ask him down the phone why he and the other bands he is touring with are so keen to avoid the "folk" tag. Very politely, he tries to explain why his solidly crafted brand of acoustic guitar-led songs is anything but folk music. "It's a strange word, because lots of people have lots of different meanings for it," says Adem. "It's acoustic music influenced by folk, definitely, but also music that couldn't exist without being in the modern day."

Folk is a word that strikes fear into the hearts of many aspiring pop musicians. Not only does it conjure up images of the terminally naff - woolly jumpers, beards, and so on - but it is also the journalist's catch-all term for legions of singer-songwriters too bland to merit a better definition: Sandi Thom, K T Tunstall and David Gray, to name just three.

Over the past year, that seemed certain to change, as a new group of musicians emerged, hovering at the edges of the mainstream. They were only loosely connected in musical style, but shared a taste for the more esoteric aspects of traditional melody and instrumentation. Before long, promoters and press started talking excitedly about a new wave of folk.

The stars of the genre, which was given various snappy tags ("weird folk" and "nu-folk" being the most common), ranged from the harpist Joanna Newsom and the nouveau-hippie troubadour Devendra Banhart, in the United States, to British bands such as King Creosote, Tunng and even the Sixties singer Vashti Bunyan, who languished in obscurity for years until her 1970 album, Just Another Diamond Day, was hailed as a lost classic. Adem has also been a leading light. He played a crucial role in the movement with his London-based Homefires festival, which introduced artists on the burgeoning scene to a wider audience.

Now, however, he and his contemporaries are kicking against the label. The Zero Degrees of Separation tour, which begins in Brighton this month, is being emphatically and somewhat self-consciously marketed as "contemporary acoustic music". Adem will team up with Vashti Bunyan, the Argentinian singer Juana Molina and members of the Californian indie band Vetiver. It's an ambitious project: rather than play separate sets, as you would at a conventional gig, the musicians will share the stage and collaborate on each other's songs.

Bunyan says she agreed to take part in the tour on condition that the promotional material avoid using the word "folk". This might sound a little disingenuous, coming from a singer who once travelled to Scotland in a horse-drawn cart, and whose debut album featured members of the Sixties folk-rock giants Fairport Convention, but Bunyan claims she was wrongly labelled.

"I never, ever thought of myself as a folk singer, and my heart turns over every time I see that word in the same sentence as my name," she says. "I was a pop singer, and my debut album happened to have folk musicians on it. Certainly for me, I drew on classical and chamber music - even Fifties pop music - much more than I ever did on traditional folk."

Adem, who incorporates elements of electronica in his work, says his approach to music sticks out "like a sore thumb" when compared to conventional folk. "My music couldn't exist without Björk or Aphex Twin, whereas other people making music might say they only listen to, I don't know, songs that people sang in fields."

But both artists struggle when pushed to provide an alternative description of their music. There is a lot of umm-ing and ah-ing, and the most I can elicit from Adem is a few platitudes about how he just makes what he wants to make and if anyone likes it, well, that's a bonus. "I can't think of a good term for it, but we're all nice," is the nearest he comes to a definition.

Vashti Bunyan comes a little closer when she talks about an interest in delving into the past. "I've found a lot of my audience is very young - people my age have no idea who I am. And what I find really encouraging is that younger people seem to have a huge appetite for the history of music, for its archaeology."

Despite the huge variations in how these acts sound, they all represent a culture that both plumbs the past hundred-odd years of recorded music and looks to the future. Old-style melo dies and instruments may feature, or inform the spirit of this music, but they are only part of an eclectic sweep that merges rock with jazz, electronica and, of course, folk. It's just a shame the "contemporary acoustic" tag does so little to tell us what's going on under the surface.

The Zero Degrees of Separation tour starts on 12 January at the Corn Exchange, Brighton. Further details from: www.cmntours.org.uk