Asterism: a noticeable pattern of stars that make up part of one or more constellations, but not a constellation itself. The Big Dipper, one of the most recognized asterisms in the sky, is part of the constellation Ursa Major, (The Big Bear).
Image: By Till Credner - Own work: AlltheSky.com, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20042019