The acronym IaaS stands for Infrastructure as a Service in cloud service models. IaaS provides virtualized computing resources over the Internet, allowing organizations to rent infrastructure components like servers, storage, and networking instead of purchasing and maintaining on-premises hardware. This model offers flexibility, scalability, and cost savings, enabling businesses to scale resources up or down as needed. IaaS is especially beneficial for startups and enterprises looking to reduce capital expenses while maintaining control over their IT environment.