Quark's Bar, Grill, Gaming House and Holosuite Arcade (referred simply as Quark's) was an establishment located on Deep Space 9's promenade owned and run by the Ferengi Quark. It was a popular hub for the residents and visitors to the station.
Quark's was nearly shut down in 2376 as Bajor's upcoming membership in the Federation would mean a moneyless economy for the region. However, Ferengi Grand Nagus Rom intervened, and gave Quark's diplomatic status as the Ferengi Alliance's embassy to Bajor. (DS9 novel: Unity)