Solution as a Service (SaaS) is related to software as a service that is enterprise solutions for things such as email, forums, instant messengers and self-service models for interacting with online businesses including a platform business. A SaaS terminology comes from IaaS (Infrastructure as a Service), PaaS (Platform as a Service), SaaS (Software as a Service or Solution as a Service), and next up will be XaaS (Everything as a Service).
Related Definitions in the Project: The Project Management
