A lecture hall was a building where lectures were given. In 2369, during the return trip from a psychological conference to the USS Enterprise-D, a runabout with Deanna Troi, Jean-Luc Picard, Data and Geordi La Forge aboard encountered a series of temporal fragments. When one of those caused Troi to view the others as frozen in time, Troi wasn't sure about her experience and commented that there had been moments in the conference's lecture hall she thought time was standing still, too. (TNG: "Timescape" )