In the music industry, a single is a song that is released on its own, separate from an album. It is usually the first song released from an upcoming album, and is often used to promote the album. On the other hand, the iHeartRadio app is a music streaming service that allows users to listen to a wide variety of songs, including singles, albums, and playlists. While a single may be available on the iHeartRadio app, it does not mean that it is a single in the traditional sense.