A storage bay was a type of facility in which various items were kept.
In 2153, a storage bay which contained conduit housings on Enterprise NX-01 was transformed into a command center, to deal with the Xindi threat. (ENT: "The Xindi")
In 2369, a Cardassian attack on Deep Space 9 damaged several empty storage bays on level fourteen of the station. (DS9: "Emissary")
Melora Pazlar visited a storage bay to obtain an astrometric array in 2370. (DS9: "Melora")
In 2373, Neelix's pantry was located in storage bay 3 on the USS Voyager. (VOY: "Flashback")
In 2374, Damar and Weyoun were to meet Jack, Lauren, and Patrick in a storage bay. (DS9: "Statistical Probabilities")