The word Disco is used to describe both a dance and a music style. Disco Dance is a style of dance that is typically done to disco music. It became largely popular in the 1970's in nightclubs and gained mainstream popularity with the release of the movie, Saturday Night Fever. The sound of disco music is typically a four-on-the-floor beat with a variety of instrumentation including: syncopated basslines, strings, horns, electric piano, synthesizers, and electric rhythm guitars. Disco dance began as a loose and highly improvised style. As disco evolved certain dance moves became popular and developed into mainstays for what is now most referenced as disco dance. Some common disco dance moves include: the Bump, the Penguin, the Funky Chicken, the Boogaloo, the Watergate, the Bus Stop, the Robot, and the Hustle.