A nonconforming structure is any structure which was in existence on August 1, 1973 (the effective date of the original Greene Township Zoning Ordinance) which contained a use which was permitted in the District in which it was located, but which did not conform to the District's regulations for: lot area, width or depth, front, side or rear yards; maximum height; lot coverage; or minimum livable floor area per dwelling unit or any structure which was in existence on the effective date of any amendment to this chapter which contained a use which was permitted in the District in which it was located, but which did not conform to the District's regulations for: lot area, width or depth; front, side or rear yards; maximum height; lot coverage; or minimum livable floor area per dwelling unit.