Bachelor's degree
Until the 19th century, a bachelor's degree represented the first degree in a particular faculty, with Arts representing undergraduate study, thus the Bachelor of Civil Law (BCL) at Oxford and the Bachelor of Laws (LLB) at Cambridge, for example, were postgraduate degrees. Vestiges of this system still remain in the ancient universities, with Oxford and Cambridge awarding BAs for undergraduate degrees in both arts and sciences (although both award undergraduate BTh degrees through associated theological colleges, and Oxford awards BFA degrees in addition to the BA) and defining other bachelor's degrees (e.g. BPhil, BCL) as postgraduate awards equivalent to master's degrees, although many postgraduate bachelor's degrees have now been replaced by equivalent master's degrees (e.g. LLM for the LLB at Cambridge and MSc for the BSc at Oxford). The same historical usage of indicating an undergraduate degree by it being in the faculty of arts rather than being a bachelor's degree gives rise to the Oxbridge MA and the Scottish MA).
Graduate school
Although graduate school programs are distinct from undergraduate degree programs, graduate instruction (in the US, Australia and other countries) is often offered by some of the same senior academic staff and departments who teach undergraduate courses. Unlike in undergraduate programs, however, it is less common 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.