frontier

noun

fron·​tier ˌfrən-ˈtir 

ˈfrən-ˌtir,

frän-ˈtir,

ˈfrän-ˌtir 

1

a

: a border between two countries

the frontier between Canada and the U.S.

b

obsolete : a stronghold on a frontier

2

a

: a region that forms the margin of settled or developed territory

were sent on an expedition to explore the western frontier

b

: the farthermost limits of knowledge or achievement in a particular subject

frontiers in immunology

c

: a line of division between different or opposed things

the frontiers separating science and the humanities

—R. W. Clark

d

: a new field for exploitative or developmental activity

… the brain lies before us as one of the last scientific frontiers here on earth.

—Robert Klitzman

frontier adjective

Synonyms

• border
• borderland
• march

Examples of frontier in a Sentence

the frontier between Canada and the U.S.

They were sent on an expedition to explore the western frontier.

Recent Examples on the Web

With new capabilities being added to AI systems at a steady rate—in October, frontier AI lab Anthropic introduced the ability for its model to directly control a computer, still in beta—the complexity of governing this technology will only increase. —Tharin Pillay, TIME, 5 Nov. 2024

This series in collaboration with the cast and crew has proven there is a hunger to explore new frontiers in an episodic format, where actors have freedom to challenge themselves and take risks. —Nick Caruso, TVLine, 4 Nov. 2024

Nieva: One interesting thing about this moment is the big AI frontier labs are getting tons of attention. —Richard Nieva, Forbes, 31 Oct. 2024

The frontier region has been particularly tense this month. —David Brennan, ABC News, 24 Oct. 2024

Word History

Etymology

Middle English fronter, from Anglo-French frountere, fronter, from front

First Known Use

15th century, in the meaning defined at sense 1a

Kids Definition

frontier

noun

fron·​tier ˌfrən-ˈti(ə)r  frän- 

1

: a border between two countries

2

a

: a region that forms the edge of the settled part of a country

b

: the outer limits of knowledge or achievement

the frontiers of science

frontier adjective