noun. the part of a country that borders another country; boundary; border. the land or territory that forms the furthest extent of a country's settled or inhabited regions. Often frontiers. the limit of knowledge or the most advanced achievement in a particular field: the frontiers of physics.

What does being a frontier mean?

A frontier represents uncharted territory. It could be a remote piece of land or a new field of study, but if someone calls it "the frontier," you are challenged to explore it.

What is an example of frontier?

The definition of a frontier a border between two countries, or the outer limit of what has been explored. The border between United States and Canada is an example of a frontier. When there is a new plot of land that has never been explored, this is an example of a new frontier. ... The border between two countries.