"Sharpless" refers to a specific type of astronomical object known as a Shapley object, which is a catalog of bright nebulae. These nebulae are regions in space filled with gas and dust, often where new stars are born. The catalog was created by the American astronomer David Sharpless in the 1950s and includes various emission nebulae, which emit light due to ionized gas. The Sharpless catalog contains over 300 entries, each designated by a number. These objects are important for studying stellar formation and the composition of the interstellar medium. Astronomers use the catalog to identify and observe these fascinating regions in the universe.