asterism

noun as·ter·ism \ ˈas-tə-ˌri-zəm \

Definition of asterism

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)

Recent Examples of asterism from the Web

An asterism is simply a set of stars that form a pattern familiar to the human eye as part of a larger group of stars.

— National Geographic, "Reality Check: You Can’t Actually Name Stars for David Bowie," 18 Jan. 2016
In this case the asterism is made up of stars from the constellations Libra, Virgo, Centaurus, and Triangulum Australe.

— National Geographic, "Reality Check: You Can’t Actually Name Stars for David Bowie," 18 Jan. 2016
The seven stars that form the lightning pattern from Bowie’s album is in fact called an asterism.

— National Geographic, "Reality Check: You Can’t Actually Name Stars for David Bowie," 18 Jan. 2016
Many constellations display unique geometrical shapes and asterisms.

— mike lynch / sky watch, Twin Cities, "Sky Watch: The Winter Triangle is perfectly perfect this time of year," 5 Feb. 2017
As the days go on in February, the comet will quickly make a loop around the distinct Circlet asterism, a star pattern nestled within the constellation Pisces, the fishes.

— andrew fazekas, National Geographic, "Lunar Eclipse and 10 More Can’t-Miss Sky Events in February," 1 Feb. 2017
In this case the asterism is made up of stars from the constellations Libra, Virgo, Centaurus, and Triangulum Australe.

— National Geographic, "Reality Check: You Can’t Actually Name Stars for David Bowie," 18 Jan. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'asterism.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.