Form is the shape and flow of a musical arrangement just like we have a form to our day, a beginning middle and end, there is also form in music.
And just like during our day, there are transitions into smaller segments, music contains these aspects as well.

The common forms that most people know are the verse/chorus format used in popular music. There are other forms that were popular some years ago and these forms are the 12-bar blues AABA and A A’ (prime).

The 12-bar blues form is made up of 3 sections: statement, statement, summary. Each section is 4 measures long which equals 12 total bars.

AABA form usually consists of 32 measures broken into 4/8 measure segments. Each “A” segment is the same and the repetition is broken up by the “B” segment that adds a little bit of difference.

A A’ form is similar to the ABA form in that it also usually has 32 measures, but these measures are broken up into two 16-measure segments. In the verse/chorus format, each verse is usually 8 to 16 measures long and the chorus is usually 8 to 16 measures long as well. Sometimes you will also have a bridge or what is called a pre chorus. At the end of a verse/chorus song, the chorus is usually repeated or you might have what is called a vamp.

In older forms like ABAA and AA’ there are usually intros, outros and sometimes transitions between sections. There are also special endings called shout courses that are alternate melodies used at the end of a piece.

These are just some of the forms used in music there are several others that are more or less common. It may be difficult to hear form in the beginning but after you practice listening two forms it will get easier with time. One way that helped me learn, was to break each song down into 8 measures. I would dare say that the majority of the music we listen to can be broken down into 4 or 8 measure segments. If you listen to jazz or classical music you will hear different phrase lengths more often, but most popular music is broken down into 4 or 8 measure phrases.

To use this to your advantage listen to an 8 measure phrase and then see if it repeats itself at some point during the song then you can check all of the sections that are repeating and usually that helps you decipher the form.