She sat on a what?

We're all familiar with the childhood nursery rhyme which deals with that gluttonous arachnophobe, Miss Muffet, but did you know that this is the first, and only historical English usage we have of the word 'tuffet'? From it springs the assumption that a tuffet was a piece of mediaeval furniture in common use but to this day, nobody really knows for sure what, precisely, a tuffet was.

Stick that in your curds and eat it.

Source: "At Home: A short history of Private Life" by Bill Bryson.