circumference
American
noun
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the boundary of a specific area or geometric figure, esp of a circle
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the length of a closed geometric curve, esp of a circle. The circumference of a circle is equal to the diameter multiplied by π
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The boundary line of a circle.
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The boundary line of a figure, area, or object.
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The length of such a boundary. The circumference of a circle is computed by multiplying the diameter by pi.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of circumference
1350–1400; Middle English < Late Latin circumferentia, equivalent to circum- circum- + fer- (stem of ferre to carry) + -entia -ence
Explanation
The distance around a circle is called the circumference, and although circumference is often used when talking about round things, it can mean a boundary of any shape that completely surrounds something. It’s no coincidence that the first part of circumference looks like circle. The Latin word circum means “around,” and the root ferre is the Latin verb for “carry,” so imagine carrying a puppy around a circle pit of lava: the path you walk is the circumference. If you want to buy a new hat, you’ll need to measure the circumference of your head, and patrolling the circumference of your castle is a good way to protect against dragons.
Vocabulary lists containing circumference
100 Words Every Middle Schooler Should Know
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Essential Academic Vocabulary for Middle School Students, List 1
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Pi Day Vocabulary
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Even when used on its own, waist circumference performed nearly as well.
From Science Daily ● Aug. 31, 2026
Using either BMI or waist circumference provided a better balance between correctly identifying people with obesity and avoiding false-positive diagnoses.
From Science Daily ● Aug. 31, 2026
Head circumference is commonly used as a general indicator of brain size in newborns.
From Science Daily ● Jul. 17, 2026
And it was a nerve-shredding putt from inside three feet that travelled most of the circumference of the hole before dropping that deservedly saw Korda home.
From BBC ● Jun. 8, 2026
With them he deduced the circumference of the Earth with an error of only a few percent, a remarkable achievement for 2,200 years ago.
From "Cosmos" by Carl Sagan
The helmets are marked as large, for head circumferences between 22.5 to 25 inches.
From Washington Times ● Mar. 10, 2023
Helmet sizes are measured by head circumference, and helmets usually come with adjustable dials to accommodate a range of circumferences.
From Washington Post ● Mar. 21, 2022
During an inspection Dec. 15, Sampson observed “numerous” branches with 2- to 8-inch circumferences that were severed by the aerial saw and allowed to fall from 150 feet above, according to the violation notice.
From Los Angeles Times ● Mar. 2, 2022
A meager set is a set contained in the countable union of nowhere dense sets, such as the circumference of a circle in the plane, or finitely or countably many such circumferences.
From Scientific American ● Aug. 16, 2021
Circles of this kind were continually being cut by the circumferences of other circles....
From Child and Country A Book of the Younger Generation by Will Levington Comfort
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
