What does "Grandfathered" mean?

Any structure, lot or use legally in existence on 2/25/1965 is "grandfathered". This means that although a use, structure, or lot would not be permitted in a particular zoning district today, it is legal if at the time it was created it met the requirements of the zone where it is located. Another term to describe this situation is "non-conforming". There may be restrictions on expanding a grandfathered structure or use.