Diegetic and no diegetic sounds.

Diegetic refers to the world of the text.
Examples: dialogue, sound effects, music with a source within the text(radio).

Non diegetic refers to everything outside the world of text.
Examples: voice covers, sound tracks, captions and title subtitles.

On screen sound is when the audience can see the source of the sound.
Off screen sound is when the audience can not see the source of the sound. Off screen sound enables the extension of the diegetic world.