1. Any building or structure designed and occupied exclusively for residence purposes by not more than two families.
2. A building designed for and occupied exclusively by one family is a SINGLE FAMILY PRIVATE DWELLING.
3. A building designed for and occupied exclusively by two families is a TWO-FAMILY PRIVATE DWELLING.
4. PRIVATE DWELLINGS shall also be deemed to include a series of one-family or two-family DWELLING UNITS each of which faces or is accessible to a legal street or public thoroughfare provided that each such DWELLING UNIT is equipped as a separate DWELLING UNIT with all essential services, and also provided that each such unit is arranged so that it may be approved as a legal one-family or two-family dwelling.