fron·​tier | \ ˌfrən-ˈtir How to pronounce frontier (audio) , ˈfrən-ˌtir, frän-ˈtir, ˈfrän-ˌtir How to pronounce frontier (audio) \

Definition of frontier

1a : a border between two countries the frontier between Canada and the U.S.
b obsolete : a stronghold on a frontier
2a : 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

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Other Words from frontier

frontier adjective

Synonyms for frontier


border, borderland, march

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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

Cookies will boldly go into the final frontier, after the first cookies in space are baked on the International Space Station. Doug Criss, CNN, "5 things to know for June 28: Democratic debate, G20, Supreme Court, India, Alabama," 28 June 2019 The Party is moving to the left, as everyone has been saying since 2016, and the first few minutes of the debate allowed you to measure how far: Warren, who not long ago defined the progressive frontier, now seemed at the center. Benjamin Wallace-wells, The New Yorker, "At the Democratic Debate, Elizabeth Warren’s Reformism Versus Trump’s Moral Crisis," 27 June 2019 Designer Pierpaolo Piccioli crossed frontiers, mixed high and low, and blurred cultural boundaries to bring back an encyclopedic show. Thomas Adamson And Colleen Barry,, "What (the runways say) guys will be wearing for summer 2020," 24 June 2019 In the half-century since its construction began, Missouri’s Gateway Arch has been many things: a monument to Thomas Jefferson’s historic frontier, a commemoration of Lewis and Clark’s epic expedition—and, most recently, a national park. Jacqueline Kehoe, National Geographic, "What to do at Gateway Arch National Park," 21 May 2019 At the end of its second season, Westworld teased a new frontier: the world outside the park. Chloe Foussianes, Town & Country, "Westworld Season Three Is Coming—And Its Totally Different From the First Two," 21 May 2019 Everything is mixed up in my head, everything exists simultaneously, nothing has just one meaning any more, nothing is firm any longer, not the earth, not frontiers, not people, not houses . . Lidija Haas, Harper's magazine, "New Books," 10 Apr. 2019 The frontier as a symbol not of manifest destiny but of man’s idiocy? Ty Burr,, "‘Damsel’ takes the western to unusual places," 27 June 2018 The new frontier of human brain augmentation has arrived. Kafui Dzirasa, WIRED, "A New Approach to Treat Mental Illness: Electrical Engineering," 28 June 2019

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.

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First Known Use of frontier

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

History and Etymology for frontier

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

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Statistics for frontier

Last Updated

19 Jul 2019

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Time Traveler for frontier

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

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More Definitions for frontier



English Language Learners Definition of frontier

: a border between two countries
: a distant area where few people live
: the limits of knowledge in a particular field


fron·​tier | \ ˌfrən-ˈtir How to pronounce frontier (audio) \

Kids Definition of frontier

 (Entry 1 of 2)

1 : a border between two countries
2 : the edge of the settled part of a country



Kids Definition of frontier (Entry 2 of 2)

: of, living in, or situated in the frontier frontier towns frontier families

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