When discussing music, one can refer to the "story" of music, or what it is about. For instance, Beethoven's 3rd Symphony was about Napolean
as a young political
revolutionary. Deep Purple
's Smoke On The Water was about, literally, smoke on water. Music that is about something is called Program Music.
Music which is inspired by itself rather than extra-musical implications such as the stories and legends of Program Music is called Absolute Music. This is music, literally, about nothing. No sappy romantic imagery, no stirring personal experience as impetus, just music for music's sake. It is the Seinfeld
An example of Program Music would be Sir Edward Elgar
's Enigma Variations
or Benjamin Britten
's War Requeim
. Also opera in general.
Examples of Absolute Music are Anton Webern
's Five Pieces for Orchestra and Igor Stravinsky
's Wind Octet.