Primary education is the first stage of compulsory education. It is preceded by pre-school or nursery education and is followed by secondary education. In North America this stage of education is usually known as elementary education.
In most countries, it is compulsory for children to receive primary education, though in many jurisdictions it is permissible for parents to provide it. The transition to secondary school or high school is somewhat arbitrary, but it generally occurs at about eleven or twelve years of age. Some educational systems have separate middle schools with the transition to the final stage of education taking place at around the age of fourteen.
SOURCE: Wikipedia for Schools