signature tune
US /ˈsɪɡ.nə.tʃər ˌtuːn/
UK /ˈsɪɡ.nə.tʃər ˌtuːn/
1.
a tune or song that is regularly used to introduce a particular television or radio program, or a performer or group
:
•
The orchestra played the show's signature tune as the curtain rose.
•
Every morning, the radio station starts with its familiar signature tune.