A "major" is the subject that a student at university or college will choose to specialize in. Students choose a major at school to focus on studying, and it's also possible to do a double major, which entails choosing two majors and completing the coursework for both. There is also a "minor," which is a secondary area of focus; this is optional.
Not all schools will offer every possible major--make sure to check in advance what majors the school you're applying to offers.
Here are the majors that one can choose as a music student:
Jazz Majors
Jazz Performance
Classical Majors
Classical Performance
Majors available to both jazz and classical students: