Many starships have a number of transporter rooms in addition to transporters in other locales such as cargo bays. The transporter rooms on the USS Defiant were sometimes referred to as the transporter bays. (DS9 episodes: "The Way of the Warrior", "To the Death", "Broken Link", DS9 - Gateways novel: Demons of Air and Darkness, DS9 - Mission: Gamma novels: Cathedral, Lesser Evil, DS9 novel: Warpath)