N.Y. Real Prop. Acts. Law § 782
As used in this article, the term "dwelling" shall mean any building or structure or portion thereof which is occupied in whole or in part as the home, residence or sleeping place of one or more human beings and is either rented, leased, let or hired out, to be occupied, or is occupied as the residence or home of three or more families living independently of each other; or is a garden-type maisonette dwelling project as defined in the multiple dwelling law or other similar dwellings which in their aggregate are arranged or designed to provide three or more apartments, have common facilities such as but not limited to a sewer line, water main, or heating plant and are operated as a unit under common ownership, notwithstanding that certificates of occupancy were issued for portions thereof as one or two family dwellings or that the dwellings are not a multiple dwelling as defined in the multiple dwelling law.
N.Y. Real Prop. Acts. Law § 782