Following my little visit to Wymondham yesterday, I had a look at what The Concise Oxford Dictionary Of English Placenames said about its name origin. The town name is interesting insomuch it isn’t pronounced as it looks, it’s something more akin to ‘win-dum’.
Wymondham, Norfolk. Wimundham in Domesday Book, Wimundehamia in 1150, Wimundeham in 1168. Wigmund’s ham.
So this is an Anglo-Saxon name, simply meaning the settlement or village of Wigmund, which wasn’t an uncommon name at the time. It does look like it would have pronounced as it was spelled back then, with the corruption of the town name evolving over the centuries into its shorter version today.