A bit like an elephant, a ballad is hard to define but easy to recognise.

Or so I thought. I'd never thought of a song like "Marrowbones" as being a ballad, even though it tells a story, and I'd never heard it described as such until I read this thread.

It's a bit pointless arguing over how the word is used in other genres - this is a folk music forum and it should be evident that the context is folk music. The fact that the pop world uses the word to describe something different is irrelevant.

Besides the verse form, what often distinguishes a ballad is the terrible inevitability of the narrative. You just know it is going to end badly for someone. There is no characterisation, and the the story is stripped to the bone, although there may be some strange and apparently irrelevant diversions (what has that bit with the parrot in "The Outlandish Knight" got to do with it?). Nevertheless there is scope for some arresting imagery in the language.

Of course, all that could apply to "Marrowbones", but the "feel" of the song is quite different, which is why it doesn't qualify as a ballad, in my opinion.