A boarding school is a school where pupils live within premises while being given formal instruction. The word "boarding" is used in the sense of "room and board", i.e. lodging and meals. They have existed for many centuries, and now extend across many countries. Their functioning, codes of conduct, and ethos vary greatly. Pupils in boarding schools study and live during the school year with their fellows, housemasters and housemistresses. Some boarding schools also have day pupils who attend the institution during the day and return home in the evenings.
Pupils who board at the school are called boarders, or day pupils if they don't board. Pupils may be enrolled for one to twelve years or more in boarding school. There are several types of boarders depending on the intervals at which they visit their family. Full-term boarders visit their homes at the end of an academic year, semester boarders visit their homes at the end of an academic term, weekly boarders visit their homes at weekends. There are also semi-boarders who attend a boarding school in the school hours for formal instruction and activities but return home by the end of the day. In some cultures, boarders spend the majority of their childhood and adolescent life away from their families.