perimeter

perimeter — noun

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

1.名詞B2
釋義

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

例句

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.

同義詞
  • 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

反義詞
  • interior

    the inside part rather than the outer limit

  • center

    the middle area, away from the border

用法筆記

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.

常見錯誤

❌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.名詞B2
釋義

the line that forms the outside of a flat shape.

例句

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.

同義詞
  • 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

反義詞

用法筆記

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.

常見錯誤

❌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.名詞B2
釋義

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

例句

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

同義詞
  • 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

反義詞
  • area

    measures the space inside, not the distance around

用法筆記

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.

常見錯誤

❌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.名詞C1
釋義

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

例句

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

同義詞
  • 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

反義詞
  • paint

    the inside area near the basket

  • lane

    the rectangular area closer to the basket

用法筆記

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.

常見錯誤

❌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.