A "sharded cluster" is a database architecture that divides data into smaller, more manageable pieces called "shards." Each shard is stored on a different server, allowing for better performance and scalability. This setup helps distribute the workload, making it easier to handle large amounts of data and high traffic. In a sharded cluster, each shard operates independently, which means that if one shard experiences issues, the others can continue functioning. This design is commonly used in systems like MongoDB and Cassandra, where efficient data management and quick access are essential for applications with growing datasets.