It is a key. (Why would one think of anything else?)

Several other riddles are more ribald still, really too outrageous to be asked (think butter-churn). Their inclusion in the manuscript, which was bequeathed to Exeter Cathedral by Leofric (died 1072), its first bishop, is an indication of the popular respectability of the genre, although one is struck by the images the pious monks must have contemplated as they worked their way to a solution!

The Exeter Book is damaged in places and it is not possible to know how many riddles it originally contained. There may have been one hundred, although Williamson lists only ninety-one (the numbering varies in different translations).

Because the riddles have no title and no answers are provided, there still is no consensus as to what some of them mean. But you can hazard a guess, yourself, by looking at the collection.