As used in this chapter, any inconsistent provisions of law notwithstanding, the following terms shall have the following meanings:
The City Chamberlain and in lieu thereof the Mayor.
Any unpaid tax, special ad valorem levy, special assessment or other charge imposed upon real property by or on behalf of the City or special district, which is an encumbrance on real property, and which has remained undischarged for a period of one year or more.
Any property upon which there is erected any residential, commercial or industrial building or structure except an owner-occupied single-family or two-family residence.
A lien upon fire insurance proceeds pursuant to this chapter and § 22 of the General Municipal Law.