Theme music is a piece that is often written specifically for a radio program, television program, video game or movie, and usually played during the intro, during title sequence and/or ending credits. If it is accompanied by lyrics, most often associated with the show, it is a theme song.

Theme music
Theme music
Generation of variations on theme music based on impressions of story scenes
Generation of variations on theme music based on impressions of story scenes
Generation of variations on theme music based on impressions of story scenes
Music as a mirror: the “choosing my personal theme song” exercise
On Production of Theme Music for Dramatis Personae in Teleplay
Transformation of Theme Music Based on Impressions of Stories Generated From Pictures
A Research on the Mechanism of Integrating Theme Music into Ideological and Political Work in Universities
An Aesthetical Study on the Theme Music of Legend of the Condor Heroes(1983)