The Dictionary of Medieval Latin from British Sources, begun over 100 years ago, has just been completed - the final word zythum, a type of fermented malt drink, has just been added. Oxford historian Robert Whitwell, whose aim was to publish the medieval Latin equivalent of the Oxford English Dictionary, began the project in 1913. Before now, scholars looking at British source documents had to rely on a reference book first published in the 17th century.
All dictionaries supply far more information than simply definitions or translations, and this one is no exception. It gives a picture of life in the medieval era. For instance, the entry for muzzle makes reference to a muzzle being made for a polar bear that was kept in the Tower of London; the animal had to be restrained when it was brought to fish in the river Thames. A record from a coroner's court refers to a woman who died when she fell down a well chasing her cat, which was chasing a mouse.
The dictionary, published by the British Academy, runs to 17 volumes. For more on the story, see this BBC piece.