I've always had problems using the word 'definition' when it comes to describing genres. The bit in the middle 'finit' relates to the adjective 'finite' which at least implies rigid boundaries that can't be crossed. So all examples of the genre are either 'definitely' inside or outside the 'definition'. I much prefer the Venn diagram approach.

I'm happy to use the 54 descriptors in my research work, but I'm also very happy to use the world-wide commonly accepted idea of what folk music is when discussing it with people who would recognise it, i,e, the vast majority of the planet.