frontier

American  

[fruhn-teer, fron-, fruhn-teer] / frʌnˈtɪər, frɒn-, ˈfrʌn tɪər /

noun

• frontiers
  plural

1. the part of a country that borders another country; boundary; border.

2. the land or territory that forms the furthest extent of a country's settled or inhabited regions.

3. Often frontiers.

   1. the limit of knowledge or the most advanced achievement in a particular field.

      the frontiers of physics.

   2. an outer limit in a field of endeavor, especially one in which the opportunities for research and development have not been exploited.

      the frontiers of space exploration.

4. Mathematics. boundary.

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adjective

1. of, relating to, or located on the frontier.

   a frontier town.

frontier British  

/ ˈfrʌntɪə, frʌnˈtɪə /

noun

1. 1. the region of a country bordering on another or a line, barrier, etc, marking such a boundary

   2. ( as modifier )

      a frontier post

2. 1. the edge of the settled area of a country

   2. ( as modifier )

      the frontier spirit

3. (often plural) the limit of knowledge in a particular field

   the frontiers of physics have been pushed back

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Synonym Usage

See boundary.

Other Word Forms

Derived Forms

• semifrontier
  noun
• frontierless
  adjective
• frontierlike
  adjective
• transfrontier
  adjective

Inflected Forms

Nouns

• frontiers
  plural

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Etymology

Origin of frontier

1350–1400; Middle English frounter < Old French frontier, equivalent to front (in the sense of opposite side; see front) + -ier -ier ²

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Explanation

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. The noun frontier has several meanings. It can refer to the wilderness at the edge of a settled area (picture covered wagons pushing westward) or it can mean a field of study that has not yet been explored (picture genetically engineering pet dinosaurs). Deriving from "the front line of an army," a frontier can be thought of as an offensive line in a battle — always pushing forward, trying to conquer new territory.

Example Sentences

See Examples For:

frontier frontiers

Lee said the government will invest 4.7 trillion won to support "frontier AI development projects, with the aim of achieving world-leading performance for our own AI model, a national strategic asset".

From Barron's ● Nov. 2, 2026

Molecular machines are widely seen as a promising next frontier in miniaturization.

From Science Daily ● Nov. 1, 2026

Huang has defended the approach, arguing that frontier AI labs are the first generation of startups that need tens of billions of dollars to get started, not just millions.

From Barron's ● Oct. 30, 2026

McLachlan said half of the company’s exploration capital is now spent in frontier basins, or those that are undeveloped, up from roughly 20% a few years ago.

From The Wall Street Journal ● Oct. 29, 2026

To understand the answer to this paradox, we have to remember that, until 400 B.C., the frontier of Tsushima Strait separated not rich farmers from poor hunter-gatherers but poor farmers from rich hunter-gatherers.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

The device is testing the frontiers of technology that automakers increasingly see as a lucrative subscription business.

From The Wall Street Journal ● Oct. 29, 2026

“Our aim is to help humankind to chart a safe course through its technological evolution, open new frontiers of discovery, and bring forth an age of miracles.”

From Los Angeles Times ● Oct. 27, 2026

The DMZ is one of the world's most heavily fortified frontiers, and landmine incidents have previously heightened tensions between the two countries.

From Barron's ● Oct. 12, 2026

Although the research focused on two regions of the Amazon, the scientists say its conclusions may also apply to tropical deforestation frontiers elsewhere in the world.

From Science Daily ● Sep. 21, 2026

This explains the fact that in some places the frontiers between the superstates are arbitrary.

From "1984" by George Orwell

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