fron·​tier ˌfrən-ˈtir How to pronounce frontier (audio)
ˈfrän-ˌtir How to pronounce frontier (audio)
: a border between two countries
the frontier between Canada and the U.S.
obsolete : a stronghold on a frontier
: a region that forms the margin of settled or developed territory
were sent on an expedition to explore the western frontier
: the farthermost limits of knowledge or achievement in a particular subject
frontiers in immunology
: a line of division between different or opposed things
the frontiers separating science and the humanitiesR. W. Clark
: 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

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,, 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

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'frontier.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


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

First Known Use

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

Time Traveler
The first known use of frontier was in the 15th century

Dictionary Entries Near frontier

Cite this Entry

“Frontier.” Dictionary, Merriam-Webster, Accessed 28 Jan. 2023.

Kids Definition


: a border between two countries
: a region that forms the edge of the settled part of a country
: the outer limits of knowledge or achievement
the frontiers of science
frontier adjective

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