frontier
fron|tier /fr'ʌntɪər, -t'ɪər/ (frontiers)
1 [N-COUNT]
A frontier is a border between two countries. (BRIT; in AM, usually use border)
It wasn't difficult then to cross the frontier.
2 [N-COUNT]
When you are talking about the western part of America before the twentieth century, you use frontier to refer to the area beyond the part settled by Europeans.
...a far-flung outpost on the frontier.
3 [N-COUNT] usu pl, usu N of n, adj N
The frontiers of something, especially knowledge, are the limits to which it extends.
...pushing back the frontiers of science.
...technological frontiers.
1 [N-COUNT]
A frontier is a border between two countries. (BRIT; in AM, usually use border)
It wasn't difficult then to cross the frontier.
2 [N-COUNT]
When you are talking about the western part of America before the twentieth century, you use frontier to refer to the area beyond the part settled by Europeans.
...a far-flung outpost on the frontier.
3 [N-COUNT] usu pl, usu N of n, adj N
The frontiers of something, especially knowledge, are the limits to which it extends.
...pushing back the frontiers of science.
...technological frontiers.