semicircle

noun

semi·​cir·​cle ˈse-mē-ˌsər-kəl How to pronounce semicircle (audio)
ˈse-ˌmī-, 
-mi-
Synonyms of semicirclenext
1
: a half of a circle
2
: an object or arrangement of objects in the form of a half circle
semicircular
ˌse-mē-ˈsər-kyə-lər How to pronounce semicircle (audio)
ˌse-ˌmī-, 
-mi-
adjective

Examples of semicircle in a Sentence

The children sat in a semicircle. The houses are built in a semicircle.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The newspaper photographers lay on the lawn with their cameras twinkling under the stadium lights, the musicians tuned their instruments, while farther away the uneven horizon of the city described a wide semicircle. — Cynthia Zarin, Harpers Magazine, 4 Aug. 2026 Most modern cyanobacteria have large antenna complexes (or phycobilisomes), built from proteins infused with light-absorbing pigments, that fan out from the thylakoid membrane in a large semicircle. — Quanta Magazine, 10 June 2026 The two mothers stood together, eight small caskets arrayed in a semicircle before them. — Molly Hennessy-Fiske, Washington Post, 9 May 2026 When this formula is used, a circle with a radius of 1 has an area of π, and a semicircle has an area of π ⁄ 2. — Manon Bischoff, Scientific American, 5 May 2026 See All Example Sentences for semicircle

Word History

Etymology

Latin semicirculus, from semi- + circulus circle

First Known Use

1526, in the meaning defined at sense 1

Time Traveler
The first known use of semicircle was in 1526

Rhymes for semicircle

See All Rhymes for semicircle

Browse Nearby Words

semichorus
semicircle
semicircular
See all Nearby Words

Cite this Entry

“Semicircle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/semicircle. Accessed 12 Aug. 2026.

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Kids Definition

semicircle

noun
semi·​cir·​cle ˈsem-i-ˌsər-kəl How to pronounce semicircle (audio)
1
: half of a circle
2
: an object or arrangement of objects in the form of a half circle
semicircular
ˌsem-i-ˈsər-kyə-lər How to pronounce semicircle (audio)
adjective

More from Merriam-Webster on semicircle

Thesaurus: All synonyms and antonyms for semicircle

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