VR stands for Virtual Reality, a computer-generated landscape or environment, which users can interact with. VR environments have many uses. They can be used for training simulations, recreation, gaming, education, and even as a graphical interface for very sophisticated computer networks. Computer networks which require a physical user to interact with a virtual enviromnent are harder for other computers to hack into using automated methods such as dictionary-attack password hacks, but are paradoxically more vulnerable to amateur hackers who are simply good at general puzzle-solving.
VR still requires specialized goggles and sometimes full bodysuits to interact with and experience properly, holographic technology in human space never having quite progressed to the levels of Star Trek-style holodecks. The Tech Infantry used specialized full bodysuits attached to an articulated framework for training simulations, with bases and larger troop transports being equipped with one or more simulation rooms with facilities for entire platoons or even larger units to take part in the same training simulation.