A semester is a division of the academic year used by many educational institutions, such as high schools and universities. Typically, a semester lasts around 15 to 18 weeks and is designed to organize the academic schedule. Students usually take multiple courses during this time, with each course contributing to their overall progress toward graduation. In a typical academic year, there are usually two main semesters: the fall semester and the spring semester. Some institutions also offer a shorter summer semester for additional courses. Each semester includes periods for registration, classes, exams, and breaks, helping students manage their studies effectively.