This noun denotes a spectacle or sight—something observed, whether a public event, theatrical performance, or noteworthy scene. Classical usage included religious embassies to festivals, attendance at games or theater, and the general act of viewing. Luke uses it to describe the crowds returning from Jesus's crucifixion after witnessing the spectacle. The term can emphasize either the thing seen or the act of seeing it. It's related to θεωρέω (to look at, behold) and θεατρίζω (to make a spectacle of), all sharing the root sense of viewing or being viewed.