Other forms: frontiers
A frontier is the border of a country, or the edge of what is known. Cross the frontier, the frontiers of science, a frontier town.
The second sense is the one that has grown — the frontiers of knowledge, a new frontier — and it always suggests something waiting to be opened. In American history the frontier was the moving edge of settlement, a phrase that hid the people already there.
1nounfrontierThe border of a country, or the edge of what is known.
“Soldiers guarded the frontier between the two countries.”
frontier is a border.
Old French frontier comes from front, the forehead or front, from Latin frons. A frontier is the face a country turns outward.
Old French
fronter
Middle English
frounter
English, today
frontier
From Middle English frounter, from Old French fronter (whence Modern French frontière), from front.
Etymology from Wiktionary, CC BY-SA