The “Turn Around” is a concept you should recognize in music. I treat the idea of a “Turn Around” the same as an Intro or Outro. In general terms It signifies a piece of the composition that serves as Time Indicator. A time indicator is just that. Something that tells you where you are located musically. Are you on the first BAR in the second verse nearing the end? etc. Although this page will deal with the concept of the Turn Around within the confines of 12 BAR Blues arch-types, the information here is useful for any genre.
Intro thus describes the same concept as Turn Around but is always located at the start of the song. You play the Intro before the verse actually starts. You can see this in the video below where the Intro is “added” before the verse.
Outro is the Anti-thesis of an Intro. It’s the same thing essentially but played at the end of the musical composition.
In 12 BAR Blues the Turn Around is performed in BAR NR: 11 and 12 – The last two BARs
In this Overview video we can see 3 different variations of a “Turn Around” in a 12 BAR Blues composition. The Intro, Outro and Turn Around are all interchangeable.