a part of the town was originally known as "kaupangen borgund". the old norse word "kaupang" means ""marketplace"" or ""town"", thus the market town for borgund. the old norse form of the current name was "álasund". the first element of that (probably) is the plural genitive case of "áll" which means "eel" and the last element is "sund" which means "strait" or "sound". before 1921, the name was written "aalesund".