semicircle

noun

semi·​cir·​cle ˈse-mē-ˌsər-kəl 

ˈse-ˌmī-, 

-mi-

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 

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

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

The coaches gathered the players into a large semicircle on the 30-yard line. — Cheri Lucas Rowlands, Longreads, 21 Apr. 2026

Word History

Etymology

Latin semicirculus, from semi- + circulus circle

First Known Use

1526, in the meaning defined at sense 1

Rhymes for semicircle

• encircle
• tubercle
• cercle
• circle
• preopercle

Kids Definition

semicircle

noun

semi·​cir·​cle ˈsem-i-ˌsər-kəl 

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 

adjective