According to my basic terminology: *Host
Your real computer, on which the emulator/virtualizer software runs.
Host means both your real hardware and the operating system that controls that hardware. In some cases there can be only hardware without operating system, like VMware ESX.
The term "Host" describes both hardware and OS.
This can be devided to: *Host Hardware - your real hardware *Host Operating System - the operating system that controls that real hardware.
*Guest (also known as VM=Virtual Machine)
Your emulated computer, virtual machine, or VM for short, this is what you are trying to emulate. Your target. It can be the same, or very different from your real system.
For example, your host can be a Pentium III PC, while your guest can be a Sony Playstation. Of course, VirtualBox cannot emulate Playstations, so look at different software. It's just important that you understand those two basic concepts.
-This means both your virtual hardware _and_ an operating system that runs on your virtual hardware.
This can be devided to: Guest Hardware - your virtual hardware (can be anything, let's as wild as Playstation, for emulation case - usually this would be x86 PC) Guest Operating System - your OS, that runs on the virtual hardware. (can be anything, let's as wild as Playstation BIOS - but usually this would be Windows or Linux OS)
*Hyperviser/Virtualizer Software that does (Full/Para) virtualization.
*Hypercall Just like there are system calls, For para-virtual cases there are hyper calls. Actually a language between the para-virtualizer (hyperviser) and guest. Other types of virtualization doesn't use hypercalls.
Your term "virtual machine server" would be confusing. This is because the "server" term has usually something to do with networking, while virtualization can work nicely without networks, listening TCP ports, etc... Let's leave the term "server" to the programs that listen to TCP ports. Now if I understand you correctly, your term "virtual machine server" equals to my term "Host hardware" or "Host".
Additionally, those terms I just described are a LOT shorter than your terms, plus they are more accurate. It's a lot better to have accurate and short terms at once.