Platform as a service (PaaS) is a cloud computing model in which a third-party provider delivers hardware and software tools -- usually those needed for application development -- to users over the internet.
Private platform as a service (private PaaS) is software that facilitates development, deployment and operations for IT on a private infrastructure or behind a firewall.
Red Hat OpenShift is a multifaceted, open source container application platform from Red Hat Inc. for the development, deployment and management of applications.
SPI is an acronym for the most common cloud computing service models, software as a service, platform as a service and infrastructure as a service.
The Azure Fabric Controller (FC) is the part of the Windows Azure platform that monitors and manages virtual and physical servers and coordinates resources for software applications.
XaaS is a general, collective term that refers to the delivery of anything as a service.