An alumnus (male) or alumna (female) is, by BTU definition, anyone who has attended a school or university for at least one semester. Thus, former students do not necessarily have to be graduates to be considered alumni.

Alumni can be organised in alumni clubs, by creating a network of former students of a faculty or a particular study course (subject-related), or in alumni groups called regional chapters. These regional chapters consist of alumni from different faculties and study courses that are native to the same geographic area, country, or region within a country.

Alumni regional chapters can be differently organised, but typically consist of a few board members who maintain possible websites or communication platforms, handle all contact maintenance, and arrange meetings and conferences for the members of their chapter