Marazion [ˌmærəˈzaɪən] is a market town at the eastern end of Mount’s Bay and its name has caused an awful lot of confusion and has even led some poor souls to hypothesise that the ancient Cornish were a lost tribe of Israel!
There is no confusion about the first element maraz, which derives from the Cornish marghas meaning “market”. There are a few other names containing this element, including the wonderful Marazanvose [ˌmarəzənˈvəʊz] (“the market by the wall”) between Truro and Perranporth.
Current opinion is that name Marazion derives from the Cornish marghas byghan meaning “small market”. The change of → [v] in later forms of the name, and its subsequent elision, are both rather irregular.
But what about the Jewish connection? Well, here is where things get a bit murky.
An alternative name for the town used to be Market Jew. Indeed, the main street in Penzance, which ultimately leads east to Marazion, is called Market Jew Street. However, this name derives from the Cornish marghas yow, meaning “Thursday market” and really refers to a separate settlement near Marazion and now absorbed by it, a process which apparently began around 1600.
One can easily see that some…er…more imaginative types might have been led by the jew element and the supposed zion element of the names to leap to somewhat daft conclusions.

Panorama of Marazion from St. Michael’s Mount
“and it’s subsequent elision”
er… its
Ta.