AS meaning in Academic & Science ?

A students' union, also known by many other names, is a student organization present in many colleges, universities, and high schools. In higher education, the students' union is often accorded its own building on the campus, dedicated to social, organizational activities, representation, and academic support of the membership.

In the United States, student union often only refers to a physical building owned by the university with the purpose of providing services for students without a governing body. This building is also referred to as a student activity center, although the Association of College Unions International (largely US-based) has hundreds of campus organizational members. Outside the US, student union and students' union more often refer to a representative body, as distinct from a student activity centre building.