Karaoke (bimoraic clipped compound of Japanese kara "empty" and ōkesutora "orchestra") was a form of interactive entertainment or video game in which an amateur singer sings along with recorded music (a music video) using a microphone and public address system. The music is typically a well-known popular song minus the lead vocal. Lyrics are usually displayed on a video screen, along with a moving symbol, changing colour, or music video images, to guide the singer. In some countries, namely China and Cambodia, a karaoke box is called a KTV. It is also a term used by recording engineers translated as "empty track" meaning there is no vocal track. The global karaoke market has been estimated to be worth nearly $1 billion.