circumference

noun

cir·​cum·​fer·​ence sər-ˈkəm(p)-f(ə-)rən(t)s 

sə-,

-fərn(t)s

1

: the perimeter of a circle

The circle measures 22 inches in circumference.

2

: the external boundary or surface of a figure or object : periphery

from the center to the circumference of the sphere

circumferential

sər-ˌkəm(p)-fə-ˈren(t)-shəl 

sə-

adjective

Did you know?

Attempts have been made to measure the circumference of the earth since the time of Aristotle. The calculation that Columbus was relying on led him to think he could reach China by sailing west more quickly than by sailing east. But that measurement had calculated the earth's circumference as about a quarter too small, and the rest is history. Columbus wasn't the only one who got it wrong; many later attempts continued to produce different measurements for the earth's circumference—even though the Greeks had calculated it correctly way back in the 3rd century B.C.

Synonyms

• girth

Examples of circumference in a Sentence

What is the circumference of the Earth at the equator?

The circle is 38 inches in circumference.

The fence marks the circumference of the field.

Recent Examples on the Web

The high-capacity, fiber-optic cable that will link five continents will span a fantastic 31,000 miles (50,000 km) – for reference, the circumference of the Earth is 24,901 miles (40,075 km). —David Szondy, New Atlas, 1 Mar. 2025

At the start of the study, participants provided detailed information about their eating habits, lifestyle, and medical history, and had measurements taken for their height, weight, and waist circumference. —Emily Kay Votruba, EverydayHealth.com, 26 Feb. 2025

Lay out the tubes in concentric circles around the circumference of the tree. —Nan Sterman, San Diego Union-Tribune, 1 Feb. 2025

Using a pairing knife, slice a thin line around each apple’s circumference, just piercing the skin of the fruit. —Nick Siano, Miami Herald, 27 Jan. 2025

Word History

Etymology

Middle English, from Middle French & Latin; Middle French, from Latin circumferentia, from circumferre to carry around, from circum- + ferre to carry — more at bear

First Known Use

14th century, in the meaning defined at sense 1

Kids Definition

circumference

noun

cir·​cum·​fer·​ence sə(r)-ˈkəm(p)-fərn(t)s 

-f(ə-)rən(t)s

1

: a line that goes around or encloses a circle

2

: the outer boundary of a figure or area

3

: the distance around something

the circumference of the earth at the equator