bound·​ary | \ ˈbau̇n-d(ə-)rē How to pronounce boundary (audio) \
plural boundaries

Definition of boundary

: something that indicates or fixes a limit or extent Those two trees mark the boundary of our property. the mountain range that forms the country's northern boundary

Keep scrolling for more

Other Words from boundary

boundaryless \ ˈbau̇n-​d(ə-​)rē-​ləs How to pronounce boundaryless (audio) \ adjective
boundarylessness noun

Examples of boundary in a Sentence

Those two trees mark the boundary of our property. The river forms the country's western boundary. at the boundary between fact and fiction You need to set boundaries with your children. Did he violate the boundaries of the doctor-patient relationship?
See More
Recent Examples on the Web The New Shepard capsule, which was propelled over the boundary of space by a small reusable launch vehicle that returned to land vertically, will one day carry up to six passengers. Bruce Selcraig,, "Team from San Antonio’s Southwest Research Institute hopes to retrieve asteroid chunks," 16 Oct. 2020 Meanwhile, a third disturbance located near the far eastern boundary of the Caribbean Sea on Thursday is forecast to bring heavy rain to parts of the region in the next few days. Victoria Ballard,, "Two new tropical waves forecast to emerge," 15 Oct. 2020 Trump’s weight places him just over the boundary of what medical professionals consider obese. Devon Link, USA TODAY, "Fact check: Trump's hospital records, weight have not been released," 8 Oct. 2020 Residents in the area have also requested such a path that connects Richard Drive to Autumn Lane located on the northern boundary of Marquardt Park. John Benson, cleveland, "Brooklyn begins $314,000 trail addition and renovation at Marquardt Park," 30 Sep. 2020 In Summerfield, that includes the areas east of Summerfield Road, south of Stonehedge Drive and north and west of the city boundary (Annadel State Park), the Santa Rosa Police Department said. Tatiana Sanchez,, "California fires live updates: Castle winery loses major structure to Glass Fire, Calistoga residents evacuated," 28 Sep. 2020 Seminole’s rural boundary — approved by voters in 2004 — covers nearly one third of the county and limits development to either one home per five acres or one home per 10 acres. Martin E. Comas,, "SunRail, rural boundary, affordable housing among key issues for Seminole commission candidates," 22 Sep. 2020 In addition to Quitobaquito, O'odham leaders have repeatedly expressed concern about damage to other sites near the international boundary, such as tribal burial grounds and ceremonial sites that lie within the 60 feet of the international border. Rafael Carranza, The Arizona Republic, "Feds file charges against 2 O'odham women for blocking border wall construction," 17 Sep. 2020 Harris' boundary-breaking potential serves as an affirmation of the growing power of voters of color, according to nearly a dozen interviews with political strategists, potential voters and activists. Kat Stafford, Detroit Free Press, "Kamala Harris' selection as vice president resonates with Black women," 14 Aug. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'boundary.' 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 boundary

1598, in the meaning defined above

History and Etymology for boundary

bound entry 6 + -ary entry 1

Keep scrolling for more

Learn More about boundary

Time Traveler for boundary

Time Traveler

The first known use of boundary was in 1598

See more words from the same year

Statistics for boundary

Last Updated

20 Oct 2020

Cite this Entry

“Boundary.” Dictionary, Merriam-Webster, Accessed 26 Oct. 2020.

Keep scrolling for more

More Definitions for boundary


How to pronounce boundary (audio)

English Language Learners Definition of boundary

: something (such as a river, a fence, or an imaginary line) that shows where an area ends and another area begins
: a point or limit that indicates where two things become different
: unofficial rules about what should not be done : limits that define acceptable behavior


bound·​ary | \ ˈbau̇n-də-rē How to pronounce boundary (audio) , ˈbau̇n-drē \
plural boundaries

Kids Definition of boundary

: something that points out or shows a limit or end : a dividing line


plural boundaries

Legal Definition of boundary

: a theoretical line that marks the limit of an area of land

Keep scrolling for more

Comments on boundary

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


Test Your Vocabulary

Namesakes Word Quiz

  • a citrus fruit possibly named after a person
  • Which of the following is a fruit named after a Moroccan seaport?
Spell It

Can you spell these 10 commonly misspelled words?


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!