RDS, or Relational Database Service, is a cloud-based service provided by Amazon Web Services that simplifies the setup, operation, and scaling of relational databases. It supports various database engines, including MySQL, PostgreSQL, and Oracle, allowing users to choose the one that best fits their needs. With RDS, users benefit from automated backups, software patching, and monitoring, which help ensure high availability and reliability. This service is designed to handle tasks like database provisioning and scaling, enabling developers to focus more on their applications rather than database management.