Virtual reality, augmented reality, mixed reality glossary:

VR, AR, MR, XR definitions

This glossary contains definitions of specific VR (virtual reality), AR (augmented reality) and MR (mixed reality) terms and acronyms. To search for a term or a definition, simply use the search function of your browser and type the search term you’re looking for.



360 Tracking:

The minimum capability required to produce an immersive experience. 360° tracking allows the VR/AR/MR device to know the direction a given user is looking at. Also called 3DoF.


Augmented reality overlays computer-generated content on top of the real world. This superimposed digital overlay can superficially interact with the environment in real-time. AR is primarily experienced via a AR wearable glasses.

Augmented Reality Brain-Computer Interface or AR-BCI:

The ways to interact with something simulated in 3D or 2D is pre-configured and trained based on electrical signals that are being transmitted from the user’s brain via BCI.

Built-in front camera:

A front-facing camera allows the user to see the real world without taking the device off, it is a must-have for hardcore users. CPU: Central processing unit.


Degrees of freedom are the number of movement types that the user may experience. In VR, headsets offer either 3DoF or 6DoF.

Eye tracking:

By tracking the user’s gaze, the XR device renders for better sharpness and detail. Few headsets have this feature, as the technology is still complex. It can also be used for specific gaming controls.

Fish tank VR:

This type of VR experience treats users as simple spectators to only observe the content. No interaction with virtual reality environment is possible.


Field of view. The wider the field of view, the better. For reference, the human field of view (with eye rotation) reaches a maximum of 220°. Most VR headsets provide around 100 degrees.

Fresnel lenses:

Fresnel lenses and their hybrids are the most common type of lenses for virtual reality as they are thinner and lighter than normal lenses.


Graphics Processing Unit. Hand tracking: Allows for direct hand interaction or natural gestures.


Head-mounted display is a display device, worn on the users head or as part of a helmet. HUD: Heads up display. Immersion: The feeling of presence in a virtual environment, or the degree to which the human brain can be tricked.

Inside-out tracking:

The headset uses one or more front-facing cameras to detect its position, with or without the aid of markers. This type of tracking is generally less powerful and accurate than outside-in tracking.


Positional tracking system developed by Valve for SteamVR and HTC VIVE headsets. This system uses base stations (external sensors), also referred to as lighthouses.

Marker-based augmented reality:

(Also called image recognition). Using a camera and some type of visual marker, such as a QR/2D code, to produce a result only when the marker is sensed by a reader.

Markerless augmented reality:

(Also called location-based, position-based, or GPS). Widely implemented application of augmented reality, uses a GPS, digital compass, velocity meter, or accelerometer which is embedded in the device to provide data based on your location.


Mixed reality is also known as (XR/MX, immersive media, spatial computing and hybrid reality). A digital overlay that allows interactive 3D virtual elements to integrate, enrich and interact with the real-world environment.


Computer-generated objects which can be visibly obscured by objects in the physical environment.

Outside-in tracking:

Makes use of external sensors and/or cameras to accurately track the headset’s position within a delimited space (room-scaling). For full room scale, users need to install more than two sensors to avoid any occlusion.

Positional tracking:

The precise tracking of the VR headset’s position (and, therefore, the user’s position). The more precise the tracking is, the better the VR immersion. Positional tracking is a requirement for room scale capabilities.

Projection based augmented reality:

Works by projecting artificial light onto real-world surfaces. Projection based augmented reality applications allow for human interaction by sending light onto a real-world surface and then sensing the human interaction (i.e. touch) of that projected light.

Proximity sensor:

A sensor that pauses and plays experiences based on whether the headset is on the users face. RAM: Random Access Memory.

Room scale:

(World scale for Microsoft). An XR device is able to precisely position itself in 3D within a given room volume. This is currently the most advanced capability for immersive experiences. Also called 6DoF.


Software Developer Kit.

Sensor fusion:

This means multiple sensors will be able to correct themselves and nullify any respective flaws. Simulation sickness: (Also known as VR sickness or cybersickness). A good starting refresh rate is 60 Hz, although most VR headsets offer rates between 90 and 120 Hz.

Spatial Audio:

A marketing term used for the type of immersive surround sound experienced in VR. Spatial computing: This term that identifies the way users interact with computers in their surroundings. It is not restricted to a single location and can apply to the real or virtual world. Examples include how with advancements in technology, users can now interact via speech, gestures and with wearable computing gadgets.

Standalone VR:

VR that doesn’t require a PC or a smartphone. Also known as all-in-one VR, wireless VR, autonomous VR.

Superimposition based augmented reality:

Either partially or fully replaces the original view of an object with a newly augmented view of that same object. Object recognition plays a vital role because an application cannot replace the original view with an augmented one if it cannot determine what the object is.

Tethered PC VR/AR:

VR/AR headset connected by cable to a PC. Tethered virtual reality headsets are also known as desktop VR or PC VR headsets.


Virtual reality encompasses all immersive experiences and content via a VR headset or HMD (Head-mounted display). The content is 100% digital and computer generated. Current reality is replaced with a new 3D digital environment in which the user is isolated from the real world.

Windows mixed reality:

Windows MR is the content platform their VR headsets have been developed for but are in fact virtual reality devices.


Extended reality is the umbrella category that covers all the various forms of computer-altered reality, including: augmented reality (AR), mixed reality (MR), and virtual reality (VR).