(XR) is a term referring to all real-and-virtual combined environments and human-machine interactions generated by computer technology and wearables, where the 'X' represents a variable for any current or future spatial computing technologies. 
e.g. It includes representative forms such as augmented reality
(AR), mixed reality
(MR) and virtual reality
and the areas interpolated among them. The levels of virtuality range from partially sensory inputs to immersive virtuality, also called VR.