The most basic definition is that the elements of music are pitch, rhythm, and timbre put together in an order which is pleasant to listen to. We like both repetition and surprise. A montage of recorded environmental sounds could be considered music but not everyone would agree with this. There are associations with sounds and melodies which evoke memories. This adds a more complicated layer of meaning to music. Music can have a spiritual quality for some people. Music is important in all cultures but not as important as food, shelter and a job; and for most people, procreation. I don't think there is a primary human need for music but usually there is a primal desire for music. I do know of at least a couple people who could live quite happily without ever hearing music again. Music is a useful emotional enhancement for movies and games which seems to be a general direction of entertainment for the human race.