The phrase "title song" refers to a piece of music that has the same name as a movie, album, TV show, or play. It is typically the main or most recognized song from that particular work. Full definition
Question: Which vocal artist — male or female — has the most movie title songs to his or her credit? (shepherdexpress.com)
More substantial and remarkable are a scene where Chazz offers Jimmy his treasured illegal brush (which sets up a pretty cheesy childhood flashback) and a musical moment when Chazz (wielding a strap - on keyboard) is joined by Jimmy for a singing of title song «Blades of Glory.» (dvdizzy.com)
The exhibition brings to life the recently published book titled Songs for the Witch Woman. (pacificdesigncenter.com)