Sorry, I hit reply a bit too soon.
Etymology indicates the source of the word. It is related to but not coterminous with its definition. I believe, as was posted above, that the word derives fromm Venetian dialect meaning iron forge (although, since I speak neither mainstream Italian nor Venetian dialect I can’t confirm this), but regardless, the fact that a word derives from another one gives insight and color but not a full definition. This is precisely why I wrote in my first post that “functionally” the ghettos were walled and gated.
Creating a boundary (eruv) around an Orthodox Jewish neighborhood (in the old days, a wall with doors; these days a symbolic boundary, like wires strung on utility poles) allows certain activities (like carrying objects or pushing a baby carriage) to be performed on the Sabbath. So it's not necessarily a bad thing. Obviously in some places it became a bad thing but that doesn't necessary reflect on the concept.
The Toco Hills eruv is probably the best known in Atlanta. It really is a completely self-sufficient community. My vet's office is about 50 yards outside the SW boundary.