An academic is a person who works as a researcher (and usually teacher) at a university, college, or similar institution in post-secondary (tertiary) education. He or she is nearly always an advanced degree holder. In the United States, the term academic is approximately synonymous with that of the job title professor although in recent decades a growing number of institutions are also including academic or professional librarians in the category of "academic staff. " In the United Kingdom, various titles are used, typically fellow, lecturer, reader, and professor (see also academic rank), though the loose term don is often popularly substituted. The term scholar is sometimes used with equivalent meaning to that of "academic" and describes in general those who attain mastery in a research discipline. It has wider application, with it also being used to describe those whose occupation was researched prior to organised higher education.