org/wiki/Lyon#cite_note-0 has one explaination for the -s The spelling Lyons with a final {s} is probably the result of a confusion with the Norman village Lyons-la-Forêt, famous resort of the Anglo-Norman kings such as Henry I of England or Richard the Lionheart. Lyon and Lyons don't share the same etymology : Lyon is a former Lugdunum and Lyons a former *Licontio
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.