European Marks
A Mark (or March, Marches) is the European name for a border, a frontier, a “boundary” territory; its name comes from early Middle Ages. The Franks called it marka, Anglo-Saxons called it mearc, but both nations meant only one thing by the word: something that is situated between two sources of power, political and economical influence, and law.
Kirill Kobrin on borders.