You you finish a Bachelor Degree at University, you graduate, so you are a graduate. Post-graduate, refers to study carried out after you have graduated which tends to lead to a higher degree (eg: Honours, Graduate Diploma, MBA, PhD)

A graduate school (or grad school) is a school that awards advanced academic degrees, such as doctoral degrees with the general requirement that students must have earned a previous undergraduate (bachelor's) degree. Many universities award graduate degrees; a graduate school is not necessarily a separate institution. Producing original research is often a significant component of graduate studies, including the writing and defense of a thesis or dissertation. The term "graduate school" is primarily North American. Additionally, in North America, the term does not usually refer to medical school (whose students are called "medical students"), and only occasionally refers to law school or business school. (The latter types of programs are often collectively termed professional schools). Those attending graduate schools are called graduate students, or in British English postgraduate students, or, colloquially, postgrads. Degrees awarded to graduate students include master's degrees, doctoral degrees, and other postgraduate qualifications such as graduate certificates and professional degrees. Although graduate school programs are distinct experiences from undergraduate degree programs, graduate instruction (in Australia, the United States, and other countries) is often offered by some of the same senior academic staff and departments that teach undergraduate courses. Unlike in undergraduate programs, however, it is rare for graduate students to take coursework outside their specific field of study at graduate or graduate entry level. At the Ph.D. level, though, it is quite common to take courses from a wider range of study, for which some fixed portion of coursework, sometimes known as a residency, is typically required to be taken from outside the department and college of the degree-seeking candidate, to broaden the research abilities of the student. Some institutions designate separate graduate versus undergraduate staff and denote other divisions (often called School of X, e.g., diplomacy) Postgraduate education (or graduate education in North America, sometimes described as quaternary education) involves studying for degrees or other qualifications for which a first or Bachelor's degree is required, and is normally considered to be part of tertiary or higher education. In North America, this level is generally referred to as graduate school. The organization and structure of postgraduate education varies in different countries, and also in different institutions within countries. This article sets out the basic types of course and of teaching and examination methods, with some explanation of their history. In some programs in the traditional German system, there is no legal distinction between "undergraduate" and "postgraduate". In such programs, all education aims towards the Master's degree, whether introductory (Bachelor's level) or advanced (Master's level). The aim of the Bologna process is to abolish this system.

While studying for a course which requires graduation, (eg Bachelor's degree) you are an undergraduate. Once you graduate, you are a graduate. When you continue to study in a course which requires a graduate qualification, you are a postgraduate student.