Extended education flourishes all over the world. Within different cultures and sociopolitical backgrounds, it takes different terms, forms, and developments across nations. Without identifying the common concepts of extended education, we may not expect further developments in extended education research. This study examined the terms that are used to describe extended education in each country. Research focus was given to the kind of connotations the terms contain -- in what ways the terms are perceived. Given that extended education in each nation has its own heritage and historicity, the study also suggested four extended education development models. The four models mainly concern the origin of extended education -- for what reasons a certain type of extended education was introduced and developed as a legitimate educational arrangement. Finally, this current study attempted to explore the common features and concepts of extended education as an area of education research and academic discipline.