Clusters are groups of similar items or entities that are located close to each other. In various fields, such as data science, clusters help identify patterns or relationships within data. For example, in geography, a cluster of cities may indicate a region with high population density or economic activity. In biology, clusters can refer to groups of cells or organisms that share common characteristics. For instance, a cluster of stars in space may form a star cluster, where the stars are bound together by gravity. Understanding clusters allows researchers to analyze and interpret complex systems more effectively.