Karaoke (clipped compound of Japanese kara 空 "empty" and ōkesutora オーケストラ "orchestra"), is a form of interactive entertainment or video game developed in Japan in which an amateur singer sings along with recorded music (a music video) using a microphone. The music is typically an instrumental version of a well-known popular song. Lyrics are usually displayed on a video screen, along with a moving symbol, changing color, or music video images, to guide the singer. In several Asian countries such as China, Cambodia or the Philippines, a karaoke box is called a KTV. The global karaoke market has been estimated to be worth nearly $10 billion.