Open Source Cloud and Virtualization Terminology for VMware Users

Recently, as I was talking to a friend about OpenStack, oVirt, and other Open Source Cloud and Virtualization technologies, he stopped me and had me back up. This friend has a strong background in VMware technologies, but not so much with their Open Source counterparts. It occurred to me there are others who may be coming from the same VMware background, thus I decided to create a handy cheat sheet for folks new to Open Source Cloud and Virtualization technologies who have a VMware background.