A pied-à-terre (French: “foot on the ground”) is a small living unit (typically an apartment or condominium) typically located in a large city (such as Paris or New York!). It typically is used as a temporary second residence, either for part of the year, or part of the work week.
Specific to New York City: Many co-op buildings in New York City prohibit pieds-à-terre because they want full time residents.
Best Pied-à-Terre Cities: A 2007 Forbes magazine article deemed Manhattan and Hong Kong as the top choice cities for a pied-à-terre. Woot woot! Go New York!