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

Also during evening hours this month, three bright stars form an asterism known as the summer triangle. —Geoff Chester, Washington Post, 1 Sep. 2023

But this asterism—literally, a pattern of stars—is not just a pretty sight. —Phil Plait, Scientific American, 14 July 2023

Both the asterism and the seven daughters of Atlas shine against a backdrop of exquisite enamel. —Rachel Cormack, Robb Report, 28 June 2023

It’s located in the direction of the constellation Sagittarius the Archer, which happens to contain a famous asterism – or noticeable pattern of stars – called the Teapot. —Paul Douglas, Star Tribune, 19 Aug. 2020

While neither a constellation nor an asterism, the stretch of our home galaxy has been interpreted similarly to other shapes in the sky for millennia by many different cultures. —Joshua Rapp Learn, Discover Magazine, 4 Aug. 2022

The Little Dipper is another, much fainter, asterism and includes Polaris (the North Star) at the end of its handle. —Corey S Powell, Discover Magazine, 27 Mar. 2014

The Old Farmer’s Almanac says that on Halloween, look for the Pleiades asterism (a cluster of stars of similar brightness) rising in the eastern sky by 7 p.m. and fully visible after 8 p.m. —Teresa M. Hanafin, BostonGlobe.com, 30 Oct. 2022

See below for advice on how to easily find that asterism. —Jamie Carter, Forbes, 10 Oct. 2021

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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