English Reference
noun

frontier

n.
US /fɹənˈtɪɹ/ UK /fɹˈʌntiə/ fron·tier UK spelling frontier's, frontier's

  1. 01 B2 Upper Intermediate

    the line or area where one country touches another.

    the political and geographical boundary separating two countries or territories.

    Simple

    The soldiers were sent to guard the mountain frontier between the two nations.

    In context

    Tensions escalated as both nations increased their military presence along the disputed frontier, leading to a complete halt in cross-border trade.

  2. 02 C1 Advanced Academic

    the furthest point of what is known in a particular subject or activity.

    the extreme limit of understanding or achievement in a particular field.

    Simple

    Space is often called the final frontier for human exploration.

    In context

    The latest research in quantum computing represents the new frontier of modern physics, challenging our fundamental understanding of information.

  3. 03 B2 Upper Intermediate American English

    a region at the edge of a settled area, especially in historical North America.

    a region that forms the margin of settled or developed territory, often associated with historical expansion.

    Simple

    Life on the American frontier was difficult and dangerous for early settlers.

    In context

    The myth of the frontier has deeply influenced American literature, portraying the wilderness as a place of both lawless danger and infinite opportunity.

    Usage

    Often used with the definite article 'the'.

This is the same posture empires have always taken toward frontiers they didn’t build and don’t have to live inside the consequences of.

The Guardian· 31 Aug 2026

These are wrinkles that are still being ironed out, even in the largest, most cutting-edge frontier models.

Ars Technica· 13 Jul 2026

From Middle English frounter, from Old French fronter (whence Modern French frontière), from front.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Old French fronter
Level B2 · Upper Intermediate
Frequency Frequent
Updated