Radio drama (or audio drama, audio play, radio play, radio theatre, or audio theatre) is a dramatised, purely acoustic performance. With no visual component, radio drama depends on dialogue, music and sound effects to help the listener imagine the characters and story: "It is auditory in the physical dimension but equally powerful as a visual force in the psychological dimension." Radio drama includes plays specifically written for radio, docudrama, dramatized works of fiction, as well as plays originally written for the theatre, including musical theatre and opera.