frontier

The edge of a country where it meets another country or an area beyond its settled land.

• They crossed the frontier at dawn.
• Troops gathered near the northern frontier.
• The frontier between the countries follows the river.

How to use it: frontier between A and B (Soldiers guarded the frontier between the two countries.); frontier with something (They reached the country’s frontier with Spain.)

Similar words: border, boundary

Common phrases: cross the frontier, frontier town, frontier with something

The furthest point reached in knowledge or development, where new discoveries and changes happen.

• Space remains a frontier of discovery.
• Scientists are exploring new frontiers in medicine.
• Their work lies at the frontier of computer technology.

How to use it: frontier of something (She works at the frontier of medical research.)

Similar words: leading edge, cutting edge

Common phrases: frontier of science, new frontier, at the frontier

Land with few settlers, beyond areas where people have already built towns and farms.

• They built a cabin on the frontier.
• Life on the frontier was often difficult.
• Settlers moved west as the frontier expanded.

Similar words: wilderness

Common phrases: the western frontier, on the frontier, frontier life