- The paper establishes that XR should be viewed as a neutral, symbolic umbrella term for immersive realities rather than as 'Extended Reality' tied to a single concept.
- It uses historical and semantic analysis to contrast the coinage and adoption timelines of VR, AR, and MR, clarifying their divergent origins.
- The study emphasizes the need for consensus-driven standardization by SDOs to resolve semantic instability and promote interoperability in immersive technologies.
Rethinking XR and MR: Historical, Semantic, and Standardization Perspectives
Overview
The paper "XR is XR: Rethinking MR and XR as Neutral Umbrella Terms" (2603.29939) presents an in-depth analysis of the evolution, semantic instability, and standardization of terminology in the field of immersive realities, with a specific focus on VR (Virtual Reality), AR (Augmented Reality), MR (Mixed Reality), and XR ("Any Reality"). The central argument is that the term XR, often ambiguously interpreted as an abbreviation for "Extended Reality," is more appropriately regarded as a neutral, symbolic label devised for the purpose of inclusively referencing all "reality-related" technologies, rather than stemming from or tied to any single constituent concept.
The paper systematically parses the history of VR, AR, MR, and XR, distinguishing between two critical perspectives: the coinage timeline (when and how terms were introduced) and the adoption timeline (key drivers of term and technology uptake across communities). The term VR emerged in popular and technical discourse during the late 1980s, particularly via VPL Research and as early as Broderick's 1982 novel, "The Judas Mandala." AR was introduced in 1992 by Caudell and Mizell, with subsequent rigorous conceptualization (e.g., Azuma’s three defining criteria), and MR was formalized in 1994 by Milgram and Kishino as a position along the Reality-Virtuality (RV) continuum, encompassing both AR and Augmented Virtuality.
Extended Reality (XR), introduced in 1991 by Mann and Wyckoff, was not originally intended as an umbrella term. Only with the advent of platforms requiring semantic interoperability—for instance, OpenXR from the Khronos Group—did the need for a neutral, non-committal collective label for VR/AR/MR arise. The timeline analysis demonstrates that terminology coinage and term adoption often diverged in both timing and intent, subject to sociotechnical, industrial, and standardization influences.
Semantic Ambiguity and Symbolic Neutrality
A major claim of the paper is that XR is not best understood as "Extended Reality" but as an intentionally neutral symbol. In the context of standards development (e.g., OpenXR, WebXR), the letter 'X' functions as a wildcard, analogous to "any reality you like," a position also adopted in ISO/IEC 5927:2024. The paper highlights that the persistent ambiguity in XR’s meaning arises from the competing agendas of academia, industry, terminology-promoting entities, and SDOs (Standards Development Organizations).
The deficiency of MR as an all-encompassing umbrella term is noted: while MR originally served as an umbrella for AR and AV, its industrial reinterpretation—particularly Microsoft's use of "Mixed Reality" for specific AR devices—has fractured its semantic scope. The symbolic nature of XR, devoid of technical baggage, offers a practical resolution to ambiguity, thereby facilitating interoperability and discourse spanning multiple domains.
Standardization, Governance, and Stakeholder Roles
The paper emphasizes the role of SDOs (including Khronos, W3C, ISO/IEC) as crucial arbiters in stabilizing semantics in reality-related technologies. In contrast to the differentiation motivations of academia and industry, SDOs prioritize neutrality and interoperability. The analysis underscores that terminology stabilization is adapting from the unilateral proposals of individual actors toward consensus-driven governance frameworks involving academia, industry, and SDOs (e.g., panels and workshops at ISMAR and IEEE VR).
A central practical challenge highlighted is the chronic shortage of technical experts participating in standardization, resulting in diluted expertise in critical semantic decisions. The paper provides concrete examples, such as inconsistent internal use of XR within Unity Technologies’ documentation, that illustrate how large-scale industry actors, even when not explicit terminology promoters, can propagate or reinforce terminological instability.
Theoretical and Practical Implications
The clarification and consensus on umbrella terminology have direct implications for semantic interoperability across platforms, APIs, and application domains. The use of XR as a purely symbolic umbrella term dissolves conceptual inconsistencies that arise when umbrella terms are retrofitted from older, more restrictive definitions. Theoretically, the analysis in the paper informs the broader discourse in HCI, digital media, and standardization, promoting cross-disciplinary clarity.
Moreover, should the community revisit the umbrella role of MR (as recently re-proposed by Skarbez et al.), the evolving taxonomy of realities (including recent constructs such as "Multimediated Reality") must be reconsidered within a robust, standards-driven semantic framework to avoid further fragmentation.
Conclusion
This paper provides an authoritative synthesis of the historical, semantic, and governance aspects shaping XR-related terminology. The assertion that XR operates optimally as a neutral symbolic label—rather than as "Extended Reality"—is substantiated through historical analysis and the practical requirements of standardization. Stable interoperability in immersive reality technologies necessitates ongoing, expert-driven governance, with SDOs mediating consensus across the often incompatible agendas of research, industry, and terminology stakeholders. Future advances in semantic precision for immersive realities will depend on deeper collaboration and resource allocation in the standards ecosystem.
