'Walled' in the Bible

‘Likewise, if a man sells a dwelling house in a walled city, then his redemption right remains valid until a full year from its sale; his right of redemption lasts a full year.

But if it is not bought back for him within the space of a full year, then the house that is in the walled city passes permanently to its purchaser throughout his generations; it does not revert in the jubilee.