A star cluster is a group of stars that are close together in space. There are several synonyms for the term "star cluster." One such phrase is "stellar association," which refers to a loose grouping of stars that share similar properties and are often located in or near a large molecular cloud. Another synonym is "open cluster," which describes a cluster of stars that is loosely bound together by gravity. In contrast, a "globular cluster" is a tightly packed group of stars that are typically found in the halo of a galaxy. Lastly, a "stellar nursery" is a term commonly used to describe regions in which new stars are born, often within a star cluster or stellar association.