A/B testing compares two versions of a digital or learning experience to see which version works better. Users are split into two groups “A and B”, each testing a different version (like of a training or a user interface). Their engagement, understanding, or results are measured and analysed. This helps to find out which version is more effective.

Technology that overlays digital content on the real world using devices like smartphones, tablets, or AR glasses.

A physical or virtual space designed for XR experiences that involve full-body movement. In a physical arena, users may walk freely within a tracked area. In a virtual arena, it refers to a large digital play space.

Any visual, audio, or code component used in XR development – such as textures, 3D models, or sound effects.

The version of the code of an XR application that can be installed on a headset or released to users (compiled code). Builds are numbered. The first build is therefore usually the first functioning version of the written code.

The CAMIL model is a framework for designing and evaluating immersive learning in extended reality (XR). It highlights key factors for effective digital learning, such as the interaction between learners, cognitive development, engagement, control, and decision-making. These elements together support successful learning experiences in XR environments.

Classroom management refers to all the activities a teacher undertakes to create a learning environment that facilitates curricular, emotional and social learning. It includes organising lessons, setting rules and expectations, resolving conflicts and creating a positive classroom community.

Cognitive load describes the mental effort needed to process information while learning. In XR environments, it is important to reduce distractions, structure content clearly, and use interactive elements purposefully. This supports working memory, leads to deeper understanding, and ensures knowledge is retained and applied effectively.

In the broader educational debate, competence is generally understood as the combination of knowledge and skills in coping with action requirements. (BIBB, 2020)

The curriculum is the largest entity of lesson planning. The curriculum contains multiple subjects/courses and describes the content that needs to be learned to achieve a specific graduation goal.

The European Qualifications Framework (EQF) is an EU-wide framework that classifies educational qualifications into eight levels to enable comparability between educational programmes in all EU countries.

Formative assessment is essential in managing and improving learning processes by capturing the continuous feedback or behaviour of learners. Formative assessment in XR allows teachers to see their students progress in real time and adapt their teaching to their needs. XR-based formative assessments encourage active learner participation by allowing them to experiment, make mistakes and adapt their approach in real-life scenarios.

Summative assessment is a final assessment of learning outcomes. It provides a structured way of measuring learners’ knowledge, skills and competences at the end of a learning experience. In XR environments, this form of assessment can take the form of standardised tests, task completion in specific scenarios or even tracking data.

The extent of the observable environment at any given time through the headset, typically measured in degrees.

The number of frames per second (FPS) rendered in the XR application. A higher frame rate ensures smoother visuals and reduces motion sickness.

Actions performed by a player that modify the state of the game. In other words, the rules of the game that determine which actions in the game lead to which consequences.

A method where a user activates an interface or object by looking at it for a set duration, often used when controllers aren’t available. It can be particularly helpful for people with limited mobility or motion sickness.

A virtual boundary set up in XR headsets to prevent users from walking into walls or obstacles. When users get too close to the edge of the safe play area, a visual warning appears to guide them back.

Technology that simulates touch or physical feedback through vibrations or forces, enhancing immersion in XR experiences.

A wearable device (e.g., VR glasses) that displays XR content in front of the user’s eyes, often including motion tracking and audio.

Inclusion in learning environments means creating a space where diversity is recognised as the norm. The intention is that all learners feel valued and supported regardless of their background, identity or ability. In XR environments, inclusion is achieved by designing experiences that cater to different learning needs, provide accessibility and create immersive scenarios that reflect a wide range of perspectives.

Interaction that can happen between a player and an object, an NPC, or other players. Developers use the word “interaction” to write scripts, and prepare the game design.

Smallest unit of communication between educator and learner. Example: An interaction is a smaller unit than a lesson.

IPD stands for ‘Interpupillary Distance’: this is the distance between a user’s eyes. Adjusting the IPD setting ensures that the lenses of an XR headset align correctly with the eyes, improving comfort and clarity.

Theoretical comprehension of a topic as opposed to competence which also includes practical knowledge.

The delay between a user’s action and the system’s response. Low latency is critical to avoid discomfort in XR experiences.

Agency means taking control of your own learning process. In XR environments, it is crucial as they allow exploration, decision-making, and active participation. Learners can make meaningful choices, set personal goals, and engage with content independently. Educators support this by creating flexible XR experiences that foster creative problem-solving and active participation.

Learning analytics in extended reality involves using data from immersive learning experiences. It tracks user behaviour and progress in real time to enhance learning. Metrics like gaze behaviour, movements, and interactions inform teachers about comprehension and challenges. This data helps to personalise lessons and create tailored feedback while ensuring data protection and ethics.

Learning outcome or output describes the targeted competence goals defined for each learning unit. An output oriented lesson focusses on the results students are meant to produce after learning the topic.

Short for ‘low polygon count,’ this refers to 3D models created with a small number of polygons. Polygons are simple geometric shapes used, for example, to create characters or assets such as treasure chests. The more polygons there are, the more detailed the 3D model. Low poly models are visually simpler but easier to render, which improves performance on mobile and standalone XR devices.

Mixed methods blend qualitative and quantitative evaluation to better understand learning processes. This approach allows teachers to assess measurable data alongside subjective experiences in XR environments. By combining structured assessments and immersive observations, it captures learners’ achievements and engagement, helping to adapt teaching strategies while considering both progress and personal growth.

Mixed reality (MR) is an advanced form of augmented reality in which virtual and physical elements interact in real time, allowing digital objects to respond to and interact with the physical world.

NPC stands for non-player characters. Typically, these are salespeople, characters who guide users through a tutorial, or story-based characters in video games that are not played by another human being but are controlled by artificial intelligence or programming.

A 3D application created with OpenGL or WebGL: These are graphics libraries used to render interactive visualisations of XR applications. WebGL runs directly in a web browser without requiring installation. This allows XR content to be opened directly in the web browser.

The process of improving performance by reducing processing demand, often by simplifying models, textures, or scripts (e.g. Low Poly).

A feature in XR headsets (HMDs) that uses the headset’s external cameras to display the real world using a camera feed. This allows users to see their surroundings while wearing the HMD. This feature is often used for safety reasons or to blend real and virtual elements (AR or MR).

Peer feedback is a learning process in which learners give each other constructive feedback on their work, ideas or achievements. Immersive technologies enhance this by creating interactive virtual spaces for direct, visual, and tangible feedback. This fosters better understanding, critical thinking, and communication skills, boosting personal responsibility and improving learning processes.

A reusable game object or component in XR development (especially with Unity) that can be easily placed and customised in a scene.

Presence is the degree to which learners feel engaged in a learning environment. In XR settings, it involves the sensation of being “there”, interacting with digital content and peers, and feeling personally involved. Strong presence boosts motivation and understanding. Educators can enhance this by using realistic simulations and interactive elements.

Strategic management role in game development, responsible for the outcome of the project.

The process of creating a preliminary or simplified version of a software application (a prototype) to test and refine its design, functionality, and user experience

Specific help given by the educator to support the learner (e.g. vocabulary list to ensure text comprehension). In an XR app, this could be guidance while a task is being performed (tooltips, hints, tips).

A collection of software tools and libraries that developers use to build XR applications for specific platforms or devices.

A remote computer or system that stores and manages data or applications. In XR, servers can be used to host multiplayer data, track user progress, or deliver updates and assets to applications.

A tracking system for XR headsets that allows movement in all directions: forward/backward, up/down, left/right, and rotation around three axes (pitch, yaw, roll).

Practical knowledge of a topic. Being able to use knowledge in a practical action-oriented situation.

3D audio that gives the illusion of sound coming from a specific direction or location within an environment.

An XR headset that runs independently without needing to connect to a computer or smartphone.

A common movement mechanic in VR where users point to a location and ‘jump’ there instantly to reduce motion sickness.

A headset that must be connected to a powerful computer or console to run XR applications, often allowing higher performance.

The TICOL model (Theory of Immersive Collaborative Learning) designs immersive learning in extended reality. It focuses on the key dimensions that shape effective digital learning. The model emphasises technology integration, learner-digital interaction, and collaboration for effective digital learning. It promotes learner ownership and positive learning outcomes, helping educators optimise engagement and personalisation in XR.

Virtual reality (VR) is a fully immersive experience. An HMD (see head-mounted display) transports the user into a computer-generated 3D environment, which is primarily used for training, education and entertainment.

A fully functional XR environment that can be opened in a web browser via a computer, HMD (head-moutned display) or mobile device (see Open GL/ Web GL).

A collective term for immersive technologies including Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR). XR refers to all real-and-virtual combined environments.