As used in this section, the following terms shall have the meanings indicated:
NONCONFORMING STRUCTURE
A structure or building or part thereof manifestly not designed to comply with the applicable use provisions contained in this chapter or its subsequent amendment where such structure lawfully existed prior to the enactment of this chapter or amendment. Such nonconforming structures include, but are not limited to, nonconforming signs.
NONCONFORMING USE
A use, whether of land or of structure, or both, which does not comply with the applicable use provisions of this chapter or its subsequent amendments, where such use was lawfully in existence prior to the enactment of this chapter or amendment.