XaaS, or "Anything-as-a-Service," is a cloud computing model that delivers various services and resources to users over the internet, on-demand, as a service. The "X" in XaaS represents any type of service or resource that can be delivered in this manner. XaaS encompasses a wide range of offerings, including software, infrastructure, platforms, and more, which are typically delivered and consumed on a subscription basis.

The key characteristic of XaaS is its service-oriented approach, where users access and utilize services remotely via the internet, rather than managing physical infrastructure or software on-premises. This model offers several benefits, including scalability, flexibility, cost-efficiency, and simplified management, as users can easily scale resources up or down, pay only for what they use, and rely on the service provider to handle maintenance and updates.