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

Visible on clear September evenings, this seven-star asterism (a shape of stars, not an official constellation) moves into a noticeably low position in the northern sky after sunset. —Jamie Carter, Forbes.com, 16 Sep. 2025

The Summer Triangle—formed by the bright stars Vega, Altair, and Deneb—is a prominent asterism that lies along the Milky Way's path. —Harry Bennett, Space.com, 28 Aug. 2025

Our teapot asterism is actually the brightest part of the official constellation Sagittarius the Archer. —Mike Lynch, Twin Cities, 17 Aug. 2025

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

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