A soundstage is a term used in audio and video production to describe an imaginary, three-dimensional space where sounds or images are recorded. It refers to the perceived environment in which the recording takes place, including depth, height, and width. In other words, it's like creating a virtual room for recording purposes, where sound engineers can manipulate various factors such as reverb, echo, and spatial distribution of audio elements to create an immersive experience for listeners or viewers.