A student is a learner, or someone who attends an educational institution. In some nations, the English term (or its cognate in another language) is reserved for those who attend university, while a schoolchild under the age of eighteen is called a pupil in English (or an equivalent in other languages). In its widest use, student is used for anyone who is learning.A mature, non-traditional, or adult student in tertiary education (at a university or a college) is normally classified as an (undergraduate) student who is at least 21–23 years old at the start of their course and usually having been out of the education system for at least two years. Mature students can also include students who have been out of the education system for decades, or students with no secondary education. Mature students also make up graduate and postgraduate populations by demographic of age.