Projection Television or "PTV" is a term that has been used for a long time, but as technology has advanced, so have the options for projecting images. Some of the synonyms for PTV include "rear projection television", "big screen television", "front projection TV", and "digital projector". Each of these terms describes a different type of television or projector that produces a large image. "Rear projection television" typically uses a mirror to reflect an image onto a screen from behind, while "big screen television" may refer to any television with a screen larger than 50 inches. "Front projection TV" and "digital projector" both refer to devices that project an image onto a screen or wall, but may require external speakers for audio.