In cloud computing, IaaS stands for Infrastructure as a Service. It provides virtualized computing resources over the internet, allowing businesses to rent IT infrastructure—such as servers, storage, and networking—on a pay-as-you-go basis. IaaS enables organizations to scale their infrastructure according to demand without the need for significant capital investment. Popular IaaS providers, like Amazon Web Services (AWS) and Microsoft Azure, offer on-demand resources that can be provisioned and managed easily, enhancing flexibility and efficiency.