Cloud computing refers to the delivery of computing services such as storage, servers, networking, databases, software, and analytics over the internet rather than relying on local hardware and infrastructure. It enables users and organizations to access resources on-demand without the need to invest in or maintain physical infrastructure. This paradigm shifts computing from being hardware-centered to service-oriented, where resources are elastic, scalable, and billed according to usage. It allows individuals, businesses, and governments to increase efficiency, reduce costs, and improve accessibility to advanced technologies. Cloud computing differs from cluster computing and grid computing in significant ways. Cluster computing involves connecting multiple computers in a local network to act as a single system, usually to achieve high availability and performance for specific applications. It is tightly coupled, meaning all nodes in a cluster work closely together under a single management system. Grid computing, on the other hand, involves pooling resources from geographically dispersed systems to solve large-scale computational problems. Unlike clusters, grids are loosely coupled and involve heterogeneous systems working collaboratively for resource sharing. Cloud computing stands apart as it provides services over the internet through virtualization, offering on-demand resources that are scalable and flexible, without requiring users to manage the underlying physical infrastructure.