What is the purpose of the "bridge" in a song?

The purpose of the "bridge" in a song is to provide contrast and transition between sections. A bridge often serves as a departure from the established patterns of verses and choruses, introducing a fresh musical or lyrical idea that enhances the overall structure of the song. This section can create a shift in mood or energy, allowing listeners a moment of surprise or reflection, which can make the return to the familiar chorus or verse feel even more impactful.

By introducing this contrasting element, the bridge also helps to maintain the listener's interest throughout the song. It acts as a vital narrative device, often moving the song toward its climax or resolution. This skillful use of contrast is significant in shaping the emotional journey that a song conveys.