Where would we be without sound? Sound makes up most of our lives. We use it for safety reasons; like when we step out of a street because of an on coming car. And we use it for enjoyment: Like when we listen to music, or watch tv.
Sound, we live by, and for sound. If you look for a definition of sound, that definition probably sounds a little cold and to the point, not what you would really define sound as. The definition of sound says that it is a disturbance of energy that comes through matter as a wave, and that humans perceive sound by the sense of hearing. But if you ask a musician what sound is, he might define it as poetry, or as rhythm.
Why do you think so many people worry about the sound system, and the sound cards they have on their computer, or why companies like JVC worry about sound design. Some music fans even want the right media player for their sound downloads.
There are people that fine tune their ears and deal with sound every hour of the day like sound recorders, they listen to sound recording after sound recording every day, just to make sure that the sound tracks are perfect.
Sound is of major importance to some people, and sound is not sound, but music to their ears.