asterism

noun

as·​ter·​ism ˈa-stə-ˌri-zəm 

1

a

: a group of stars that form a pattern in the night sky

On October evenings, when the trees have shed their leaves and stars become visible through the twigs, our best-known asterism, the Big Dipper, passes under the north pole.

—George Lovi

Note: The term asterism does not now usually refer to a constellation but to a star pattern that makes up part of a constellation or that includes stars from more than one constellation.

b

: a small group of stars

2

: a star-shaped figure exhibited by some crystals by reflected light (as in a star sapphire) or by transmitted light (as in some mica)

Examples of asterism in a Sentence

Recent Examples on the Web

First, look out for the dazzling trio of stars that form the famous Summer Triangle asterism. — Anthony Wood, Space.com, 2 July 2026

Then locate Vega, the brightest star in the Summer Triangle asterism, rising in the eastern sky. — Jamie Carter, Forbes.com, 25 June 2026

Instead, the Big Dipper is dubbed an asterism, a distinct pattern of stars, one tiny step below a constellation. — Mike Lynch, Twin Cities, 14 June 2026

Three stars — Deneb, Vega and Altair — will form a triangle, known as the Summer Triangle asterism. — Hali Smith june 4, Idaho Statesman, 4 June 2026

Word History

Etymology

borrowed from Greek asterísmos, from asterízein "to arrange in constellations" (from aster-, astḗr "star" + -izein -ize) + -ismos -ism — more at star entry 1

First Known Use

1598, in the meaning defined at sense 1a

Rhymes for asterism

• autism
• fascism
• racism
• sikhism
• sophism
• statism
• sufism
• thomism
• tourism
• tropism
• abolitionism
• aldosteronism