As used in this article, the following terms shall have the meanings indicated:
A structure or part of a structure not designed to comply with the applicable use or extent of use provisions in this chapter, its predecessors or any amendments thereto, such as minimum yard, maximum lot coverage, maximum height and off-street parking requirements, where such structure lawfully existed prior to enactment of this chapter, its predecessors or amendments thereto. Such nonconforming structures include, but are not limited to, nonconforming signs.
A lot, the area of dimension of which was lawful prior to the adoption of this chapter, its predecessor or any amendments thereto, but which fails to conform to the requirements of the zoning district in which it is located, such as minimum lot area requirements, by reason of such adoption or amendments.
A use, whether of land or of a structure, which does not comply with the applicable use provisions in this chapter, its predecessors or any amendments thereto, where such use was lawfully in existence prior to enactment of this chapter, its predecessors or amendments thereto.