boundary

noun

bound·​ary ˈbau̇n-d(ə-)rē How to pronounce boundary (audio)
plural boundaries
Synonyms 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
boundaryless
ˈbau̇n-d(ə-)rē-ləs How to pronounce boundary (audio)
adjective
boundarylessness noun

Synonyms of boundary

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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?
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Yet even as his tenure enters its countdown, Duffy continues to lead a critical fight over the regulatory boundaries of derivatives markets. — CNBC, 28 Aug. 2026 The Environmental Protection Agency has jurisdiction over certain radiation that goes beyond the site boundary of a nuclear facility. — Los Angeles Times, 28 Aug. 2026 The measurements showed that internal dendrites formed at defects such as pores and grain-boundary junctions. — Neetika Walter, Interesting Engineering, 28 Aug. 2026 Check the numbers, name the boundary, and choose the workaround that protects both freedom and trust. — Tarot.com, The Orlando Sentinel, 28 Aug. 2026 See All Example Sentences for boundary

Word History

Etymology

bound entry 6 + -ary entry 1

First Known Use

1598, in the meaning defined above

Time Traveler
The first known use of boundary was in 1598

Phrases Containing boundary

Browse Nearby Words

bound and gagged
boundary
boundary condition
See all Nearby Words

Cite this Entry

“Boundary.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/boundary. Accessed 1 Sep. 2026.

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Kids Definition

boundary

noun
bound·​ary ˈbau̇n-d(ə-)rē How to pronounce boundary (audio)
plural boundaries
: something that points out or shows a limit or end : dividing line

Legal Definition

boundary

noun
bound·​ary
plural boundaries
: a theoretical line that marks the limit of an area of land
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