Definition of asterism
1a : 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> ◆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)
Origin and Etymology of asterism
Greek asterismos, from asterizein to arrange in constellations, from aster-, astēr
First Known Use: 1598
Seen and Heard
What made you want to look up asterism? Please tell us where you read or heard it (including the quote, if possible).