Name Origin: English, Welsh Possible Derivations: Son or descendant of Guillemin, a pet form of Guillaume, the French form of William; From the Belgic guild-helm, meaning “harnessed with a gilded helmet” or welhelm, “the shield or defense of many”; from the given name “William,” an given name combining Old French with Germanic elements: wil, meaning “desire, will” and helm, meaning “helmet” or …
https://www.thoughtco.com/williams-name-meaning-and-origin-1422645

