circumference

/səˈkʌmfərəns/ (bre, ipa) · /sərˈkʌmfərəns/ (ame, ipa) · /sər-ˈkəm(p)-f(ə-)rən(t)s sə-, -fərn(t)s/ (ame, mw)

circumference — noun

  • circumferencesingular
  • circumferencesplural

1. the outer curve that makes a circle, or the total distance measured around that

1.名詞B2
釋義

the outer curve that makes a circle, or the total distance measured around that curve.

例句

The teacher drew a circle and labeled its circumference in blue.

label the circumference on a circle diagram

Salma used the radius to work out the circle's circumference.

use the radius to find the circumference

同義詞
  • perimeter

    perimeter is the broader term for the distance around any flat shape

  • distance around

    a plain explanatory phrase rather than a technical term

文法句型

the circumference of a circle

find the circumference

用法筆記

Most often used in geometry or measurement when the shape is specifically circular. Distinguish from sense 2, which extends to other round or curved objects such as a waist, pipe, or tree trunk.

常見錯誤

❌Multiply the radius by itself to get the circumference.
✅Multiply the radius by 2π to get the circumference.
💡squaring the radius belongs to the area formula, not the distance around a circle.
❌The circumference is the space inside the circle.
✅The circumference is the line around the circle.
💡the inside space is the area, not the circumference.

2. the line around a rounded or bent thing, or the distance found by measuring all

2.名詞B2
釋義

the line around a rounded or bent thing, or the distance found by measuring all the way around it.

例句

The nurse recorded Mira's waist circumference after the checkup.

waist circumference = body measurement

Christopher wrapped a rope around the tree to find its circumference.

find the circumference of a round object

同義詞
  • girth

    often used for the measurement around a person's body or a thick object

  • perimeter

    works better for flat shapes than for body measurements

  • measurement around

    a plain descriptive phrase for learners

文法句型

the circumference of [object]

[body part] circumference

用法筆記

Common with nouns for body parts and round objects, especially in medical, clothing, or product-measurement contexts. Distinguish from sense 1: sense 2 is not limited to circles drawn in geometry.

常見錯誤

❌The bottle has a circumference of six centimetres across.
✅The bottle measures six centimetres across.
💡circumference measures around the outside, not straight from one side to the other.
❌The baby's head circumference was thirty-five square centimetres.
✅The baby's head circumference was thirty-five centimetres.
💡circumference uses length units, not square units.