The groups are the families of instruments: string, brass, woodwind and percussion; with the whole being the entire orchestra! For example, "cbofp" represents the woodwind family by listing the initials of its members: clarinet, bassoon, oboe, flute and piccolo.
Well done 'mushroomsteve' a brilliant solve. I can't beat you jetpunkers for long. Just as you state the letters are the initials of instruments in an orchestra..... vvcbh stands for Violin, Viola, Cello, Bass, Harp completing the usual string instruments. The percussion of course consists of a good many instruments and I'm sure you jetpunkers can easily work out what the initials stand for. Another Honorary Gold Medal for 'mushroomsteve'....... congratulations.
That could be the start of something good………..
But I don't want to be that mean…………………..
Maybe that noun is made of wood………………..
Now I can hear you start to sigh………………….
For this noun's second letter is Y…………………..