N.Y.C. Admin. Code § 20-242: § 20-242 Definition.

Whenever used in this subchapter the term "guide" shall mean and include any person who engages in the business of guiding or directing people to any place or point of public interest or who, in connection with any sightseeing trip or tour, describes, explains or lectures concerning any place or point of public interest to any person within the city or obtains the patronage of any person for such trip. Nothing herein contained shall be construed to include any person or persons who describes, explains or lectures concerning any place or point of public interest while aboard a sightseeing boat or vessel regularly engaged in scheduled trips around Manhattan island on navigable waters.