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

Example Sentences

the frontier between Canada and the U.S.

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

Recent Examples on the Web

The result of Rajamouli’s intense process, and the actors’ commitment to it, is a film that may lead all three to yet another new frontier: Hollywood. —Carlos Aguilar, Los Angeles Times, 16 Jan. 2023

Israel says an Iranian presence on its northern frontier is a red line that justifies its strikes on facilities and weapons inside Syria. —Bassem Mroue, BostonGlobe.com, 2 Jan. 2023

More recently, TikTok has become the new frontier of cultural production, where moving images flicker across our iPhones with a persuasive, practically irresistible kineticism. —Jason Parham, WIRED, 27 Dec. 2022

The world’s deepest frontier, which is located at the southern end of the Mariana Trench in the Pacific Ocean, lies nearly seven miles below the water’s edge. —Rachel Cormack, Robb Report, 16 Dec. 2022

Some experts see this as the next frontier in juvenile justice — an opportunity for the incoming presiding judge to press for and seek to support. —Madeline Buckley, Chicago Tribune, 12 Dec. 2022

China represents, in many ways, SARS-CoV-2’s final frontier. —Katherine J. Wu, The Atlantic, 6 Dec. 2022

Although the warring states of Lebanon and Israel have just negotiated a maritime border, the situation remains tense along their land frontier, which is still in dispute and lined with minefields and barbed-wire fencing, and surveilled by drones. —Raja Abdulrahim, New York Times, 23 Nov. 2022

Founder Mark Zuckerberg wanted the influential company to focus on the next digital frontier, the metaverse. —Dallas News, 13 Oct. 2022

See More

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