but fer real this is my thoughts on what music is
Music is a very odd thing. It can be considered a mind altering substance, a form of communication, and a way to express ourselves. For thousands of years we (humans) have been creating music, listening to music, using music for rituals and entertainment and constantly making it more advanced. You could say that birds make music but they really don't. We simply observe it as music because our minds find ways to make sense of different pitches and rhythms and even find a way to enjoy it.
It is actually a theory of mine that when we were tree dwelling monkeys we learned to appreciate "music" because you only heard things of music like quality in a place where you were least likely to get killed. Remember, birds and other musical sounding animals go silent when a very dangerous predator is around.
Music is human, it is primal, it is very advanced and it might be the reason why we have come so far as a species. Because our ears and minds could appreciate what ever we considered music we eventually wanted to mimic sounds and we developed a speech pallet and vocal chords for communication.
Im not trying to turn this into an evolution thing but i believe that music is an essential factor in our advancements as humans.
Even in todays cultures around the world, music is used to convey an emotion, atmosphere or message in many many many different ways from movies, commercials, documentaries, videos, radio and even warfare. From way back in ancient times nations would beat war drums before their arrival to scare the enemy into submission. Just as we do today. I saw a documentary on sound weapons used in the middle east. American troops would blast Slayer and Metallica through directional speakers at trenched in insurgents for sometimes days on end to break them down.
But to answer your question, I believe the definition of music is a rhythm and/or mixture of pitches (amongst many other things we observe with our sense of hearing) that stimulates the mind in an enjoyable way. Many people have what you could call odd musical taste's. Its not odd music even if it is considered noise to most. Its simply rhythms and pitches that are observed by the mind of that person to be enjoyable.
MUSIC IS THE UNIVERSAL LANGUAGE.