イヤーワーム

noun

earworm; catchy tune stuck in one's head

Music term for a melody or song fragment that repeats persistently in one's mind.

• あのCMソングがイヤーワームになって、一いち日にち中頭じゅうあたまから離はなれない。

  That commercial jingle has become an earworm and won't leave my head all day.