# frontier

/fɹənˈtɪɹ/ (US) · /fɹˈʌntiə/ (UK)

Source: https://englishreference.com/word/frontier
Updated: 2026-06-20

## Senses

### 1. a border

noun · CEFR B2

the line or area where one country touches another.

For teachers: the political and geographical boundary separating two countries or territories.

- The soldiers were sent to guard the mountain frontier between the two nations.
- Tensions escalated as both nations increased their military presence along the disputed frontier, leading to a complete halt in cross-border trade.

### 2. limit of knowledge

noun · CEFR C1 · Academic

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

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

- Space is often called the final frontier for human exploration.
- The latest research in quantum computing represents the new frontier of modern physics, challenging our fundamental understanding of information.

### 3. unsettled land

noun · CEFR B2 · American English

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

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

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

## Examples

- The explorers traveled across the frontier into unknown lands.
- Scientists are currently working at the frontier of genetic research to find a cure for the disease.
- The treaty established a new frontier along the mountain range, effectively ending decades of territorial disputes between the two neighboring nations.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.