Higher education, also called tertiary, third stage, or post-secondary education, is the non-compulsory educational level that follows the completion of a school providing a secondary education, such as a high school or secondary school. Tertiary education is normally taken to include undergraduate and postgraduate educations, as well as vocational education and training. Colleges and universities are the main institutions that provide tertiary education. Collectively, these are sometimes known as tertiary institutions. Tertiary education generally results in the receipt of certificates, diplomas, or academic degrees.