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Meaning & use

outer boundary

noun·Academic

Last updated

UK/ˌaʊtə ˈbaʊndri/
US/ˌaʊtər ˈbaʊndri/

Meanings

  1. nouncountable

    The furthest line or edge that marks where an area, territory or object ends.

    Grammar: Countable and usually with the: the outer boundary of the park.

    Patterns

    • the outer boundary of something

    Fences mark the outer boundary of the farm.

    The outer boundary of the city was once a stone wall.

    Scientists measured the outer boundary of the glacier.

  2. nouncountablefigurative

    The most extreme limit of what is allowed or possible, in a figurative sense.

    Grammar: Often figurative: pushing the outer boundary of what is acceptable.

    Patterns

    • the outer boundary of something

    The experiment tests the outer boundary of what the material can bear.

    Her proposal sat at the outer boundary of the budget.

Word forms

pluralouter boundaries

Common combinations

the outer boundary of
The outer boundary of the property is a stone wall.
mark the outer boundary
A line of trees marks the outer boundary.
extend beyond the outer boundary
The flood extended beyond the outer boundary of the park.
push the outer boundary
Explorers push the outer boundary of knowledge.
within the outer boundary
The camp lies within the outer boundary of the reserve.

Synonyms and how they differ

perimeter
Perimeter emphasizes the full line around an area, often a measured one, while outer boundary highlights the outermost edge.
periphery
Periphery refers to the outer region or fringe, not just the line.
limit
Limit is broader and can be any restriction, while outer boundary is a line or edge.
border
Border usually means a line between two political areas, whereas outer boundary can be around one area.

Opposites

centerinterior

Word family

boundary noun
a line that marks a limit
bound verb
to form the limit of something
boundless adjective
without limits
outer adjective
on the outside, far from the center

Commonly confused: outer boundary or inner boundary?

outer boundary vs inner boundary

An inner boundary is a line inside the area, such as the inside edge of a ring, while the outer boundary is the farthest edge.

Practice

A map shows the outer boundary of a national park. What does that line show?

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