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

Keep scrolling for more

Other Words from frontier

frontier adjective

Synonyms for frontier


Visit the Thesaurus for More 

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 That was the start of a long period during which the family roamed the frontier like a tribe of gypsies, selling snake oil, staging seances, telling fortunes, and effecting miracle cures. John Strausbaugh, National Review, "The Scandalous and Pioneering Victoria Woodhull," 8 Feb. 2020 The horizon was a distant frontier, a line that held little promise other than sunsets. Martin Dumont, The New York Review of Books, "Waterlines: On Writing and Sailing," 5 Feb. 2020 The Bronx is like that for most people who don’t live there: the end of the world, the last frontier, the . . David Canfield,, "Exclusive preview: Lilliam Rivera's next novel spins a Bronx-set Greek myth retelling," 30 Jan. 2020 Rael is well aware that, not too long ago, the boundary between the United States and Mexico, which is now delineated by more than seven hundred miles of fencing, was an open frontier, dotted with stone monuments. Stephania Taladrid, The New Yorker, "Border-Town Life Defies the Wall in “Borderlands”," 12 Nov. 2019 All of the western bones are in the story’s skeleton: the frontier, plus a crew of characters working to establish a peaceful point of galactic diplomacy and trade. Ani Bundel, Ars Technica, "Space cowboy successes, and failures, ahead of The Mandalorian’s Disney+ launch," 11 Nov. 2019 But the idea of physical checks on goods, even at locations away from the frontier, is likely to breach one of the EU’s negotiating red lines., "MANCHESTER, England — With time running out for a deal on Brexit, the Irish government and European Union officials have rejected the latest British thinking on how to resolve an impasse over the Irish border, a serious setback to prospects for a breakthrough.," 2 Oct. 2019 Head to America’s wild northern frontier to discover these spectacular landscapes and the wildlife that inhabits them—from moose and grizzlies to seals and orca whales. National Geographic, "Alaska Expedition: Wildlife, Fjords, and Glaciers," 10 Sep. 2019 For people living on Kenya’s resource frontiers, the drive for national development is often a process of exclusion rather than inclusion. Zoe Cormack, Quartz Africa, "Kenya’s huge wind power project might be great for the environment but not for local communities," 3 Sep. 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.

See More

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

Keep scrolling for more

Learn More about frontier

Time Traveler for frontier

Time Traveler

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

See more words from the same century

Statistics for frontier

Last Updated

15 Feb 2020

Cite this Entry

“Frontier.” Dictionary, Merriam-Webster, Accessed 27 Feb. 2020.

Keep scrolling for more

More Definitions for frontier


How to pronounce frontier (audio) How to pronounce frontier (audio)

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

Keep scrolling for more

Comments on frontier

What made you want to look up frontier? Please tell us where you read or heard it (including the quote, if possible).


See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

More Confusing Words—Quiz

  • cats on impossible timber
  • The magician ______ moved the selected card to the top of the deck.
Spell It

Can you spell these 10 commonly misspelled words?

Add Diction

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!