A university is a higher learning institution focussed on education and research. In North America, students attend university after high school in order to obtain an academic degree in any number of subjects or disciplines. Universities employ professors at a variety of levels of seniority, as instructors, mentors, researchers and lecturers. Students attend universities to learn from these professors, pursue research on their own interests and obtain either an undergraduate (BA, BSc, etc.) or graduate degree (MA, MSc, etc).
A university refers to a higher ed establishment that stands for academic freedom and the pursuit of knowledge. With roots in medieval Europe, universities can either be public (publicly-owned or receiving substantial public funding) or private institutions (non-government owned, often operating as non-profit organizations). In the United States, the term college is used colloquially when referring to a university. Those that graduate from a university are said to be alumni of that institution.