Augmented Reality (AR) – a real-world environment overlaid with virtual objects or information to enhance (augment) the user’s experience of it. 


Avatar – the representation (abstract or realistic) of a user in a virtual environment. 


CAVE – a VR display in which an image is projected onto multiple walls that surround the user, possibly with additional projections onto the ceiling and/or floor, such that a user may feel immersed in the virtual space with a very large field of view.


Degrees of Freedom (DOF) – independent ways in which an object moves in space. Six DOF indicates three spatial directions about three axes, reflecting a full range of movement in 3D space.


Field of Regard (FOR) – the amount of space (in degrees) in which visual information can be displayed around the user. 


Field of View (FOV) – the amount of the visual scene (in degrees) that can be seen at a time by the user.


An output display may have a wide:


FOR but a limited FOV; for this reason, FOV is usually used as a specification for VR displays.


Haptic feedback (haptics) – sense-of-touch feedback, simulated by vibrations or forces applied to the user’s body.


Head Mounted Display (HMD) – a visual display device worn on the head, such as a helmet or glasses, where the visual image is presented

through small monitors in front of the eyes.


Immersion – the experience of being perceptually enveloped by and actively included in a virtual environment. 


Latency – the delay or lag in system response after the user’s action. These delays can cause an uncomfortable VR experience and may reduce the feeling of realism and presence.


Mixed Reality (MR) – the combination of elements of virtual and real-world environments and objects. 


Presence – the subjective experience of “being there” in the virtual space.


Simulator sickness / cybersickness – a feeling like motion sickness that can result from using VR and related technologies. Symptoms may include nausea, dizziness, fatigue and headaches and may persist for a short time after the use of VR. Different hardware and software may make simulator sickness more or less likely, and there are many human factors that may contribute, so some people may never experience it while others are particularly susceptible. 


Stereoscopic display – a display where two slightly different images are presented separately to each eye, e.g. through an HMD, to give the perception of depth. 


Telepresence – a virtual presence in a different location to the user’s physical presence.


Teleoperation – the ability to remotely control objects in a different location to the user’s physical presence.


Tracking – measuring the user’s position, orientation, gaze, movements etc. to allow corresponding perception of and interaction with the

virtual environment. Head tracking with HMDs is particularly common, allowing the user to look around the environment by moving their head.


Virtual Environment (VE) – a computer-simulated environment, usually interactive, typically with enhanced spatial, graphical or other modal display that provides a greater level of immersion than a traditional software application.


Virtual Reality (VR) – a computer system in which the user experiences an immersive simulation. VR technologies are diverse and the term can encompass anything from a smart phone to a full body suit with multimodal feedback.