Upperclassman

A student or pupil is a learner or someone who attends an educational institution. In Britain those attending university are termed "students". In the United States, and more recently also in Britain, the term "student" is applied to both categories. In its widest use, student is used for anyone who is learning, including mid-career adults who are taking vocational education or returning to university. When speaking about learning outside an institution, "student" is also used to refer to someone who is learning a topic or who is "a student of" a certain topic or person.

In Nigeria, education is classified into four system known as 6-3-3-4 system of education. It implies six years in primary school, three years in junior secondary, three years in senior secondary and four years in the university. However, the number of years to be spent in university is mostly determined by the course of study. Some courses have longer study length than others. Those in primary school are often referred to as pupils. Those in university as well as those in secondary school are being referred to as students.

Six years of primary school education in Singapore is compulsory.

There are also schools which have the integrated programme, such as River Valley High School (Singapore), which mean they stay in the same school from Secondary 1 to Junior College 2, without having to take the "O" level examinations which most students take at the end of Secondary school.

International Schools are subject to overseas curriculums, such as the British, American, Canadian or Australian Boards.

Primary education is compulsory in Bangladesh. It's a near crime to not to send children to primary school when they are of age. But it is not a punishable crime(sending children to work instead of school is a crime). Because of the socio-economic state of Bangladesh, child labour is sometimes legal. But the guardian must ensure the primary education. Everyone who is learning in any institute or even online may be called student in Bangladesh. Sometimes students taking undergraduate education is called undergraduates and students taking post-graduate education may be called post-graduates.

Education System Of Bangladesh:

Education is free in Brunei. Darussalam not limited to government educational institutions but also private educational institutions. There are mainly two types of educational institutions: government or public, and private institutions. Several stages have to be undergone by the prospective students leading to higher qualifications, such as Bachelor's Degree.

...
Wikipedia