Emulation

Computer emulation is when one system imitates or reproduces another system. This can be done using hardware, software, or a combination of the two. However, since hardware is expensive to reproduce, most emulation is done via software. 

Virtual Machines

One of the most common types of software emulation involves running different operating systems in a virtual environment. For example, programs like Parallels Desktop, VMware, and Apple's Boot Camp allow Windows and other operating systems to run on an Intel-based Macintosh computer. Sun Microsystems' xVM VirtualBox allows multiple operating systems to be run on Windows, Mac, and Unix platforms. These applications are collectively referred to as software emulators or virtual machines, since they emulate different computer systems.

See: https://www.virtualbox.org/

Virtualization

Creating a ‘virtual’ (i.e. not real) computer (i.e. a full simulation of the hardware) on your computer using software. This allows all types of software that can work with this hardware to be installed on the ‘virtual’ computer. A virtual computer has the advantage of allowing the user to work with different configurations on the same physical machine. E.G. you can run different operating systems with different software installed at the same time – or test out different drivers / application software / utilities without changing the configuration of your real system. MS Virtual PC & VM Ware are two examples of virtualising software. An example of usage: – let’s say you want to test Linux but don’t want to remove your current set up and install Linux on your computer, nor do you want to make a dual boot system. Using Virtualisation software you create a virtual PC and install Linux on that. You can then run Linux and test it on the virtual PC without affecting your current setup at all.

Console Emulators