Asterism in astronomy refers to a recognizable pattern of stars in the night sky that is not officially classified as a constellation. These patterns can be formed by stars from different constellations and are often used by stargazers to navigate or identify specific areas of the sky. Examples of asterisms include the Big Dipper and the Summer Triangle. Asterisms can vary in size and complexity, ranging from simple groupings of a few stars to larger formations that include many stars. While they are not officially recognized by the International Astronomical Union, asterisms hold cultural and historical significance, often appearing in folklore and guiding ancient navigators.