In some CD players and cassette players there were a function called AB, A+B, A/B that allowed you to repeat either one track or portion of a track. I used it to listen to my favorite part of a song, or to write down the text of a song.
I really miss this function in Spotify. Repeat track is implemented, but not the ability to repeat a portion of a song.
On the CD players you pushed the button once to start the sequense, then pushed it again, when you wanted it to end. Then it repeated that area of the song, as long as you wanted.