boundary

boundary — noun

1. a line, real or imagined, that shows where one place, area, or property ends and

1.nounC1
Definition

a line, real or imagined, that shows where one place, area, or property ends and another begins.

Example

Workers marked the boundary between the two farms with white posts.

pattern: the boundary between A and B

A low stone wall follows the boundary of the old school yard.

pattern: the boundary of + place

Common collocations
  • boundary between two fields
  • city boundary
  • property boundary
  • natural boundary
Synonyms
  • border

    more common in everyday talk, especially for countries

  • edge

    broader and less exact; it is not always a dividing line

  • limit

    focuses on the furthest point rather than separation between two areas

Antonyms
  • centre

    the middle area rather than the outer dividing line

Grammar Patterns

the boundary between A and B

the boundary of + place

property boundary

Usage Note

Common with between, of, and property. This sense can describe an official line on a map or an unseen dividing point in the real world.

Common Mistakes

The fence is in the boundary of our land.
The fence is on the boundary of our land.
Use 'on' for a line that marks an edge.

2. the point where one area of thought, study, or principle stops and another start

2.nounC1
Definition

the point where one area of thought, study, or principle stops and another starts.

Example

The course explores the boundary between history and politics.

pattern: the boundary between A and B

New phone cameras blur the boundary between work tools and toys.

pattern: blur the boundary between A and B

Common collocations
  • blur the boundary
  • boundary between science and art
  • boundary of free speech
  • legal boundary
Synonyms
  • limit

    more general; it does not always suggest two areas meeting

  • line

    less formal and often shorter in speech, as in 'the line between fact and fiction'

  • scope

    focuses on how much a subject covers, not the dividing point itself

Grammar Patterns

the boundary between A and B

the boundary of + principle/topic

blur the boundary

Usage Note

Often appears with between when two fields overlap, and with of when the discussion is about a rule or principle. Distinguish from noun/1, which is about places or physical areas.

3. the line of behaviour that a person or group is willing to accept from others.

3.nounC1
Definition

the line of behaviour that a person or group is willing to accept from others.

Example

Nadia set clear boundaries about work calls after 9 p.m.

pattern: set boundaries

The teacher stopped the joke because it crossed a professional boundary.

pattern: cross a boundary

Common collocations
  • personal boundaries
  • clear boundaries
  • healthy boundaries
  • cross a boundary
Synonyms
  • limit

    broader and less personal; it can refer to ability or quantity as well

  • line

    informal, often used in phrases like 'cross the line'

  • rule

    more explicit and fixed, while boundaries can be personal or emotional

Grammar Patterns

set boundaries

respect someone's boundaries

cross a boundary

Usage Note

Usually plural when talking about personal or social rules. Distinguish from noun/2: this sense is about behaviour people allow, not the edge of an idea or field.

Common Mistakes

You must respect her boundary.
You must respect her boundaries.
This sense is often plural when someone has several personal limits.

4. the rope, line, or similar marker around the outside of the cricket field.

4.noun
Definition

the rope, line, or similar marker around the outside of the cricket field.

Example

The fielder ran to the boundary and saved two runs.

pattern: to the boundary

Fans sat beyond the boundary on folding chairs near the grass bank.

pattern: beyond the boundary

Common collocations
  • boundary rope
  • boundary line
  • beyond the boundary
  • inside the boundary
Synonyms
  • boundary rope

    more exact when the edge is marked with a rope

  • line

    shorter and less specific; context must show it is the field edge

  • perimeter

    more formal and not used as often in cricket talk

Grammar Patterns

to the boundary

beyond the boundary

boundary rope

Usage Note

Used in cricket reports and commentary. It names the marked edge of the field, not the scoring shot in noun/5.

5. in cricket, a shot that carries the ball to or beyond the field edge for either

5.noun
Definition

in cricket, a shot that carries the ball to or beyond the field edge for either four runs or six.

Example

Zane opened the innings with a boundary past the diving fielder.

pattern: hit a boundary

Two late boundaries, one for four and one for six, lifted the tired crowd.

pattern: score boundaries

Common collocations
  • hit a boundary
  • opening boundary
  • two boundaries in the over
  • boundary for four
Synonyms
  • four

    specifically a boundary that reaches the edge after touching the ground

  • six

    specifically a boundary that clears the edge without first bouncing

  • scoring shot

    much broader; it can mean any shot that brings runs

Grammar Patterns

hit a boundary

score boundaries

boundary for four

Usage Note

Often countable in match reports: three boundaries, seven boundaries. A boundary can bring four or six runs, depending on how the ball reaches the edge.

Common Mistakes

He scored a boundary, so the team got six runs.
He scored a boundary, so the team got four or six runs.
This word covers both results, not only six.
Idioms

push the boundaries/limits

idiom

To try to do something that is more advanced or extreme than what is usually done or allowed.

Maya pushed the boundaries of her art with a new painting style.

Did Diego push his limits during the marathon last weekend?

Word family

  • boundaryless
    adjectiveC2

Synonym discussion

Sense: noun/1

For noun/1, 'boundary' is a slightly formal word for the line that separates one area from another. 'Border' is the everyday choice for countries, and it can also mean the area close to that line. 'Limit' is broader: it means the furthest point allowed or possible, so it often lacks the picture of two sides meeting. 'Frontier' can mean a national border, but it often suggests the outer edge of a country or a less settled region. 'Edge' is the widest and least exact of these words. Use 'boundary' when separation matters: a property boundary, a city boundary, or the boundary between two regions. Use 'limit' when the idea is 'no further'.

border ↗limit ↗frontier ↗edge ↗

Common collocations

Nouns

  • boundary line
  • property boundary
  • personal boundaries

Phrases

  • set boundaries
  • cross a boundary
  • blur the boundary between A and B

Prepositions

  • boundary between A and B
  • boundary of + place/topic

Etymology

English

The word 'boundary' was formed in English from 'bound', meaning a limit, together with the suffix '-ary'. It first referred to a marked limit around land or an area. Later, English speakers extended it to less physical ideas too, such as the line between subjects or the personal lines people do not want others to cross.