A finishing school is an institution which offers training in cultural values and norms. Most are designed for women only, and as the name implies, people attend the school after their basic education is completed, “finishing” their education with instruction in how to live in society. Many such schools focus specifically on upper class values, generating cultured, polite women who tend to do very well in society, thanks to their extensive training.
The length of a session at finishing school varies. Some programs last up to a year, while others offer much shorter, intensive terms. Women at the school are expected to conduct themselves in a well mannered way, and many schools have dress codes and other behavior requirements which are designed to remind students of the basic rules of polite behavior.
Obviously, etiquette is a big part of finishing school, and etiquette courses include everything from being a well mannered hostess to meeting foreign dignitaries. In addition to etiquette, students also learn about a variety of activities. Many schools offer instruction in the arts, such as painting and dance, and they also offer instruction in things like tennis, riding, skiing, and so forth, ensuring that their graduates will be able to enjoy themselves in a variety of situations. Language instruction has also classically been offered at this type of school.
Much of the instruction at such a school historically focused on refinement of already existing skills. Upper class women should already have been well versed in etiquette, for example, and many had already developed skills in sports and the arts. However, finishing school would have refined those skills, preparing women for a wide variety of social situations and showing them how to comport themselves as adults.
Finishing schools have greatly declined in the modern age, although some certainly do still exist, and some people bemoan the passing of the tradition. The term has also been used pejoratively to refer to women's colleges which are designed to graduate compliant, cultured women who intend to marry immediately, rather than pursuing careers.