“Potsherd” is an English compound word merging the Latin “pottis,” referring to pottery, and “shard,” from the Old English “sceard,” meaning “notched” or “broken.” This term is most commonly used in archaeology, where digs can reveal potsherds and other artifacts that tell stories about ancient civilizations. But mudlarking — searching the mud of riverbanks for valuable artifacts — is a popular hobby in London on the Thames River, which has been the site of more than 2,000 years of continuous human activity. The shifting water line gives easy access to a rich source of potsherds.