A school is an institution designed for teaching students (or "students") under the supervision of a teacher. Most countries have a formal education system, which is generally mandatory. In this system, students progress through a series of schools. Names for these schools vary by country (discussed in the Regional section below), but generally include primary schools for young children and secondary schools for adolescents who have completed primary education. In addition to core schools, students in certain countries may also have access to and attend schools both before and after primary and secondary education. Kindergarten or pre-school provides schools for some very young children (usually 3-5 years old). Universities, vocational schools, colleges or seminaries may be available after high school. A school may also be dedicated to one particular field, such as an economic school or dance school. Alternative schools can provide non-traditional curricula and methods.
There are also non-government schools, called private schools. Private schools may be for children with special needs when the government cannot provide special schools for them; religious, such as Islamic schools, Christian schools, hawzas, yeshivas and others, or schools that have higher education standards or try to develop other personal achievements. Schools for adults include corporate training institutions and military education and training.