cir·​cum·​fer·​ence | \ sər-ˈkəm(p)-fərn(t)s How to pronounce circumference (audio) , sə-, -f(ə-)rən(t)s \

Definition of circumference

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

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Other Words from circumference

circumferential \ sər-​ˌkəm(p)-​fə-​ˈren(t)-​shəl How to pronounce circumference (audio) , sə-​ \ adjective

Synonyms for circumference


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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.

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.
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Recent Examples on the Web Winners are determined using a formula based on the tree's height, circumference, and crown span (the spread of its branches). Rita Pelczar, Better Homes & Gardens, "Meet America’s Biggest Trees and Prepare to Feel Awed by These Amazing Giants," 29 Apr. 2021 In fact, measuring waist circumference should go hand-in-hand with stepping on a scale as part of any health assessment, according to new guidelines published Thursday by the American Heart Association in the journal Circulation. Sandee Lamotte, CNN, "It's time to measure your waistline, according to new recommendations. Belly fat raises your risk for disease," 22 Apr. 2021 For example, a 2014 literature review found that intermittent fasting can cause weight loss of 3-8% over 3-24 weeks and the study participants also lost 4-7% of their waist circumference but whether that was a loss of visceral fat is unclear. Misha Gajewski, Forbes, "Intermittent Fasting Makes It Harder To Get Rid Of Belly Fat, Animal Study Finds," 2 Mar. 2021 Riders can easily adjust their helmet using a dial on the back, and this helmet comes in one standard size fitting riders with a head circumference of 58 to 62 centimeters. Hanna Horvath, NBC News, "7 best bike helmets for 2021 and how to choose one," 7 Apr. 2021 The new circular supercollider will sit next to its predecessor at CERN in Switzerland, but will be nearly three times its size, with a circumference of 100 kilometers. Andrea Willige, Forbes, "Particle Accelerators That Clean Power Plants – And A Lot More," 18 Mar. 2021 Sunday, March 14 is both the annual ritual of changing clocks and the yearly celebration of the mathematical constant π (pi), which is the ratio of a circle's circumference to its diameter. Kelly Tyko, USA TODAY, "Pi Day 2021 deals: Celebrate daylight savings time change with $3.14 pizza specials at 7-Eleven, Blaze, more," 14 Mar. 2021 March 14 is Pi Day, the annual celebration of the mathematical constant π (pi), which is the ratio of a circle's circumference to its diameter. Kelly Tyko, The Arizona Republic, "Happy Pi Day! Here's where you can get pizza deals at restaurants around Arizona," 14 Mar. 2021 The Greeks used formal geometric proofs to estimate the circumference-to-diameter ratio. Randyn Charles Bartholomew, Scientific American, "Let's Use Tau--It's Easier Than Pi," 25 June 2014

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'circumference.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of circumference

14th century, in the meaning defined at sense 1

History and Etymology for circumference

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

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Time Traveler for circumference

Time Traveler

The first known use of circumference was in the 14th century

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Statistics for circumference

Last Updated

8 May 2021

Cite this Entry

“Circumference.” Dictionary, Merriam-Webster, Accessed 9 May. 2021.

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More Definitions for circumference



English Language Learners Definition of circumference

: the length of a line that goes around something or that makes a circle or other round shape
: the outer edge of a shape or area


cir·​cum·​fer·​ence | \ sər-ˈkəm-fə-rəns How to pronounce circumference (audio) , -fərns \

Kids Definition of circumference

1 : the line that goes around a circle
2 : a boundary line enclosing an area A fence marks the circumference of the yard.
3 : the distance around something

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Comments on circumference

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