Songforms

Pop (and all other) songs are built out of sections. Function-wise we have classic standardized sections:

Verse: 

Chorus (or refrain):

Bridge:

Intro:

Outro:

Coda:

Link (Connector):

Pre-chorus:

Beside these there are sections that cannot be determined functio-wise.

There are some standardized ways to arrange them. Like the two-bridge model: 

(intro) | Verse (once or twice) | Bridge (or Refrain) | 
        | Verse (once or twice) | Bridge (or Refrain) | Verse or Outro |

For example "Crazy Little Thing Called Love".