A semester is a division of the academic year used by many educational institutions, such as colleges and universities. Typically, an academic year is divided into two main semesters: the fall semester and the spring semester. Each semester usually lasts around 15 to 18 weeks, during which students attend classes, complete assignments, and take exams. Some institutions also offer a shorter summer semester or winter session for additional courses. Semesters help organize the curriculum, allowing students to focus on a specific set of subjects during a defined period. This structure aids in planning and pacing academic progress.