boundary

noun

bound·​ary ˈbau̇n-d(ə-)rē 

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

ˈbau̇n-d(ə-)rē-ləs 

adjective

boundarylessness noun

Synonyms

• limit
• limitation
• confines
• line

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

The northern boundary is below the base and includes part of northern Pulaski County. —Arkansas Online, 6 Sep. 2025

Gentle sweeps and curves are better than straight rows that merely repeat the legal lines of your property boundaries. —Neil Sperry, Fort Worth Star-Telegram, 5 Sep. 2025

That includes structural inspections, an environmental assessment, a detailed review of property boundaries, ADA compliance, staffing needs, long-term governance, funding models and partnerships. —Nour Rahal, Freep.com, 5 Sep. 2025

Eli’s visionary approach to horror, combined with Snoop’s unparalleled creative energy, promises a film that will push boundaries and captivate audiences. —Jazz Tangcay, Variety, 5 Sep. 2025

Word History

Etymology

bound entry 6 + -ary entry 1

First Known Use

1598, in the meaning defined above

Phrases Containing boundary

• boundary layer
• K-T boundary

Kids Definition

boundary

noun

bound·​ary ˈbau̇n-d(ə-)rē 

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