IaaS - Infrastructure as a Service
The most basic category of commercial cloud computing services. With Infrastructure as a Service (IaaS), you rent IT infrastructure—servers and virtual machines (VMs), storage, networks, operating systems—from a cloud provider.
PaaS - Platform as a Service
These are cloud computing services that supply an on-demand environment for developing, testing, delivering, and managing software applications. PaaS is designed to make it easier for developers to quickly create applications (e.g., web, mobile apps), without worrying about setting up or managing the underlying infrastructure of servers, storage, network, and databases needed for development.
SaaS - Software as a Service
A method for delivering software applications over the Internet, on demand and typically on a subscription basis. With SaaS, Cloud Service Providers (CSPs) host and manage the application software and underlying infrastructure, and handle any maintenance, like software upgrades and security patching. Users connect to the application over the Internet, usually by a web browser on their phone, tablet, or PC.
CPS - Cloud Professional Services
Cloud requires a variety of Cloud Professional Services (CPS) including advisory, implementation, integration, and maintenance. These services can either be bundled with products/solutions or separated into other contracts. Many example projects, templates, and FedRAMP-approved vendors can be found under Resources.