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

For the 29th year, GQ’s annual Men of the Year is giving it up to bold boundary breakers, the men and women who pushed culture into new frontiers in 2024—on their own terms. —Gq, Vogue, 4 Nov. 2024

The shift announced Thursday will bring more of the revolutionary AI technology that Google already has been baking into its dominant search engine to the digital maps service that the internet company launched nearly 20 years ago as part of its efforts to expand into new frontiers. —Sasha Rogelberg, Fortune, 31 Oct. 2024

Genre: Western Any film set in the American West that focuses on the struggles and conflicts associated with the frontier (though these themes can also be presented in modern contexts, i.e., neo-westerns). —Joe Reid, Vulture, 30 Oct. 2024

But most presidential candidates refrain from discussing space policy on the campaign trail in meaningful detail, leaving voters in the dark on their visions for the final frontier. —Thomas G. Roberts, The Conversation, 23 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