n.a melody used to identify a performer or a dance band or radio/tv program
同义词：signaturetheme song
英汉双解大词典
signature tune(signaturetunes)
1.
N-COUNT（可数名词）
Asignature tuneis the tune which is always played at the beginning or end of a particular television or radio programme, or which people associate with a particular performer. (电视或广播节目的)开始曲; 结束曲 [英国英语]