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

Example Sentences

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 Before the cleaning run starts, toss every iffy household item behind the boundary. WIRED, 24 Mar. 2023 The frontal boundary that is expected to bring storms on Friday could stall out over south Alabama and then lift back to the north as a warm front on Sunday. Leigh Morgan, al, 23 Mar. 2023 Stangle says the county hopes to concentrate most of that growth into the urban growth boundary the county adopted in 2006, keeping most of the development north of U.S.-192 and leaving the rural southern end largely untouched. Trevor Fraser, Orlando Sentinel, 23 Mar. 2023 Caffarelli set about tackling this problem in the 1970s by examining the properties of the differential equations and found that the boundary of the contact surface has no cracks or corners—if the obstacle is also smooth. Manon Bischoff, Scientific American, 23 Mar. 2023 As the story goes, for years after these battles, a red bandera (flag in Spanish) was flown at the site to mark the boundary between Spanish and Indian hunting grounds. Amanda Ogle, Travel + Leisure, 23 Mar. 2023 However, the hottest part of back-side chip (relative to the boundary of the chip) was about 45 percent hotter than the hottest part of a front-side chip. IEEE Spectrum, 22 Mar. 2023 Most decline those who do not live within a strict geographic boundary, but communities are ballooning in size nonetheless. Diti Kohli,, 19 Mar. 2023 Troops of the two countries have often clashed along this contentious boundary, leaving several soldiers dead over the years. Mimansa Verma, Quartz, 17 Mar. 2023 See More

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.

Word History

First Known Use

1598, in the meaning defined above

Time Traveler
The first known use of boundary was in 1598

Dictionary Entries Near boundary

Cite this Entry

“Boundary.” Dictionary, Merriam-Webster, Accessed 29 Mar. 2023.

Kids Definition


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


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

More from Merriam-Webster on boundary

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