The term "school year" refers to a period of time that begins in late summer or early fall and ends in late spring or early summer. It is typically used to describe the academic calendar for primary, secondary, and post-secondary education institutions, which includes the periods of instruction, examinations, vacation breaks, and other important dates. The length of a school year can vary depending on the country, region, or educational institution, but it generally ranges from 170 to 200 days for elementary and secondary schools, and from 30 to 40 weeks for colleges and universities.