When asked this question, I s-o-o-o wish there was a space for FOLK MUSIC. Then again, there's great folk music in all the genres, so would that category be superfluous? I think not.
Whilst noting that much music is described by multiple genres, it is a handy way of giving a general idea of musical style. WE know what we mean when we talk about a genre, but how does that come across to other individuals' mind-sets?