The University of Cambridge has a long tradition of academic dress, which it traditionally refers to as academical dress. Almost every degree which is awarded by the University has its own distinct gown in addition to having its own hood. Undergraduates wear college gowns which have subtle differences enabling the wearer's college to be determined. Academic dress is worn quite often in Cambridge on formal, and sometimes informal, occasions, and there are a number of rules and customs governing when and how it is worn. Black gowns (undress) are worn at less formal events, while on special days (such as the days of General Admission to Degrees) full academical dress is worn, consisting of gown, hood and headdress with Doctors in festal dress. The University's officials also have ancient forms of academic dress, unique to the University.
Most undergraduates buy or borrow a gown in their first week at Cambridge for the purpose of matriculation, which is the formal ceremony of enrolment in the University. It is more common to buy a gown, especially at the more traditional colleges, as the number of occasions on which it is worn quickly repays the investment. Gowns are often recycled between 'generations', as new graduate students in turn need to upgrade their gowns at the start of the year.
In most colleges, gowns are worn to Formal Hall (formal dinner, held every night in some colleges, once or twice a term in a few others) and to Chapel. Various College events also demand academic dress; for example, in the Trinity College regulations for members in statu pupillari, it specifies that certain senior members of College (such as the Dean) prefer students to wear a gown when addressing them in their official capacity (often when having been "deaned" for breaking the College Rules). The extent to which these rules apply vary greatly from college to college, some dispensing with academic attire even for formal hall.
On special occasions, fuller academic dress is used, including hoods. Gowns are always worn with a hood to graduation ceremonies at the Senate House, and the University sets out strict rules regarding which gown and hood a graduating student should wear, and with what. Hoods may also be worn when attending chapel with Choir Dress or a surplice.