minor
n. countablen. someone who is not yet an adult in the eyes of the law. In a university setting, it is also a secondary subject that you study alongside your main one.
n. a person under the age of full legal responsibility. In North American higher education, it refers to a secondary academic discipline requiring fewer credits than a major.
The shop cannot sell alcohol to a minor.
She decided to pursue a major in history with a minor in political science to broaden her career options.
Legal protections for a minor differ significantly from those afforded to adults, particularly regarding the capacity to enter into binding contracts or consent to certain medical procedures.
In the academic sense, it is often used with the preposition 'in' ('a minor in Economics').