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  

/ frʌnˈtɪə, ˈfrʌntɪə /

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

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

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

"The capabilities of frontier models are rapidly accelerating," the company said.

From BBC ● Aug. 19, 2026

A steady buzz is growing around China as advanced robotics emerges as the next frontier of the global AI boom, encompassing both investor enthusiasm and alarm from rivals such as the United States.

From Barron's ● Aug. 19, 2026

We’re working very closely with all the frontier players to make sure that together we can both create a great experience for people who prefer to start there.

From The Wall Street Journal ● Aug. 14, 2026

Post believes that Wall Street is underestimating the social-media giant’s ability to monetize its AI assets, including frontier models and custom chips.

From MarketWatch ● Aug. 14, 2026

And Whitney Young, for me, was pure frontier.

From "Becoming" by Michelle Obama

Terry says Qantas is conquering "one of the last frontiers in commercial aviation".

From BBC ● Jun. 26, 2026

"This study opens up new frontiers in research on human evolution," adds Professor Eleanor Scerri of the Max Planck Institute of Geoanthropology, also senior author of the study.

From Science Daily ● May 3, 2026

Pyongyang closed its borders in January 2020 to stop the spread of the coronavirus, with research and media reports indicating that the diplomatically isolated nation spent subsequent years bolstering security along its frontiers.

From Barron's ● Apr. 28, 2026

What happened to manned missions opening new frontiers?

From The Wall Street Journal ● Apr. 15, 2026

He could not control the news, and the front page was a source of continuous aggravation to a man who wanted life to be cut into symmetrical quadrants and accessible frontiers.

From "The Great Santini" by Pat Conroy