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
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
Robert Klitzman
frontier
adjective
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
The American frontier was a brutal place, but no more brutal than a zombie apocalypse.
—Erik Kain, Forbes, 11 Jan. 2025
America at the frontier of energy security and energy technology, finally fighting to win the global competition and pulling along jobs and opportunity at the local level.
—Justine Calma, The Verge, 10 Jan. 2025
The setting is the Utah Territory in 1857, where, as North and South hurtle towards war, different factions battle for control of the frontier.
—Judy Berman, TIME, 9 Jan. 2025
But as fans of frontier stories know, there’s really nothing new under the Western sun.
—Chris Vognar, New York Times, 9 Jan. 2025
See all Example Sentences for frontier 
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Erik Kain, Forbes, 11 Jan. 2025
America at the frontier of energy security and energy technology, finally fighting to win the global competition and pulling along jobs and opportunity at the local level.
—Justine Calma, The Verge, 10 Jan. 2025
The setting is the Utah Territory in 1857, where, as North and South hurtle towards war, different factions battle for control of the frontier.
—Judy Berman, TIME, 9 Jan. 2025
But as fans of frontier stories know, there’s really nothing new under the Western sun.
—Chris Vognar, New York Times, 9 Jan. 2025
See all Example Sentences for frontier
Dictionary Entries Near frontier
Cite this Entry
“Frontier.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/frontier. Accessed 18 Jan. 2025.
Copy CitationKids Definition
frontier
noun
fron·tier
ˌfrən-ˈti(ə)r
frän-
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
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