DIEGETIC VS. NON DIEGETIC SOUND

What is the difference between diegetic and non diegetic sound? What is an example of each that you can think of from a film?

   Diegetic sound is when you an see sound on screen. For example, when you see people talking (dialogue), hear explosions, rain, or footsteps (sound effects), and music thats played by a sound system. Non-diegetic sound is when it comes from a source that isn't present or given in the story's universe. For example, music that is used to bring emotions into the story (score) or sometimes they have commentary or narration by an actor.