perimeter

perimeter — noun

1. the marked or guarded limit around a place, especially land or a site.

1.nounB2
Definition

the marked or guarded limit around a place, especially land or a site.

Example

Guards walked the perimeter of the airport fence before sunrise.

walk the perimeter = check the boundary

Yellow tape marked the perimeter after the gas leak downtown.

Common collocations
  • patrol the perimeter
  • secure the perimeter
  • perimeter fence
  • perimeter wall
  • inside the perimeter
Synonyms
  • boundary

    the broadest word for a line that marks where something ends

  • border

    often sounds more official or geographic

  • edge

    more everyday and less focused on a marked limit

  • limits

    often used for the outer extent of an area

Antonyms
  • interior

    the inside part rather than the outer limit

  • center

    the middle area, away from the border

Usage Note

Often appears with words such as fence, wall, patrol, security, and inside or outside. Distinguish from sense 3: this sense names the boundary itself, not the measurement around it.

Common Mistakes

Police closed the perimeter for two miles.
Police closed the area around the stadium for two miles.
perimeter is the border itself, not the whole surrounding area.
The farm perimeter is 300 square meters.
The farm perimeter is 300 meters.
perimeter in measurement uses length units, not square units.

2. the line that forms the outside of a flat shape.

2.nounB2
Definition

the line that forms the outside of a flat shape.

Example

In class, Mia drew a square and colored its perimeter red.

geometry: mark a shape's perimeter

The worksheet asks students to trace the perimeter of each triangle.

Common collocations
  • trace the perimeter
  • follow the perimeter
  • perimeter of a triangle
  • perimeter of a square
  • draw the perimeter
Synonyms
  • outline

    focuses on the visible outer line of a shape

  • boundary line

    a clearer phrase when teaching geometry

  • edge

    can mean one side only, so it is less exact

Antonyms

Usage Note

Mostly used in geometry with nouns such as square, triangle, circle, and rectangle. Distinguish from sense 3: sense 2 is the line you can draw or trace, while sense 3 is the number you get by measuring it.

Common Mistakes

Find the perimeter by multiplying length and width.
Find the area by multiplying length and width.
perimeter is found by adding the lengths around the shape.
Color the perimeter inside the square.
Color the area inside the square.
perimeter is only the outside line, not the whole inside space.

3. the measurement found by adding the lengths all around a shape or area.

3.nounB2
Definition

the measurement found by adding the lengths all around a shape or area.

Example

The builder measured the garden's perimeter before buying wire fence.

measure the perimeter

Add all four sides to find the rectangle's perimeter.

find the perimeter by adding side lengths

Common collocations
  • calculate the perimeter
  • measure the perimeter
  • perimeter in meters
  • perimeter of the garden
  • total perimeter
Synonyms
  • circumference

    used mainly for circles and round objects

  • girth

    often used for the distance around a person's body or a round object

  • boundary length

    a technical phrase for the total distance around

Antonyms
  • area

    measures the space inside, not the distance around

Usage Note

Usually appears with measure, calculate, find, or with numbers and length units such as meters or kilometers. Distinguish from sense 1 and sense 2: those senses refer to the boundary line itself, while this sense refers to its total length.

Common Mistakes

The room's perimeter is 30 square meters.
The room's perimeter is 30 meters.
perimeter uses length units, not units for area.
The blue paint is the playground's perimeter.
The blue line marks the playground perimeter.
with no number, you usually mean the boundary itself, not the measurement.

4. the outside area in basketball play, where players pass or shoot away from the b

4.nounC1
Definition

the outside area in basketball play, where players pass or shoot away from the basket.

Example

The coach wants two shooters waiting on the perimeter.

basketball: on the perimeter

Lena caught the pass and moved the ball around the perimeter.

around the perimeter = passing outside

Common collocations
  • on the perimeter
  • around the perimeter
  • back to the perimeter
  • perimeter shooting
  • perimeter pass
Synonyms
  • outside

    common basketball shorthand for the outer area away from the basket

  • arc

    can refer more specifically to the three-point line area

  • wing

    one side area, so it is narrower than perimeter

Antonyms
  • paint

    the inside area near the basket

  • lane

    the rectangular area closer to the basket

Usage Note

Basketball use only. It often appears with on, around, or back to the perimeter, and usually describes guards, shooters, or ball movement away from the basket.

Common Mistakes

The striker stayed on the perimeter all game.
The guard stayed on the perimeter all game.
this sense belongs to basketball, not soccer.
The team kept passing on the border.
The team kept passing around the perimeter.
basketball English normally uses perimeter for this outer court area.

Synonym discussion

Sense: noun/1

Boundary is the broadest choice for a line that marks where something ends. Border often suggests a more official or geographic division, especially between countries, regions, or properties. Edge is more everyday and can mean the outer part of almost anything, so it is less exact than perimeter. Outline usually describes the visible shape of an object rather than a fence, wall, or guarded limit around land. Perimeter is especially useful when the outside limit is being marked, checked, or protected. You patrol a perimeter, but you usually draw an outline. You may cross a border, but security officers guard a perimeter around an airport.

boundary ↗border ↗edge ↗outline ↗

Common collocations

Prepositions

Etymology

GreekLate LatinFrenchEnglish

Perimeter comes from a Greek word built from the ideas of 'around' and 'measure'. It passed through Late Latin and French before entering English, which is why the modern word still suggests measuring all the way around something.