# Metaverse Architectures: A Comprehensive Systematic Review of Definitions and Frameworks
## 3 Results
### Thematic Categorisation of Metaverse Definition  
The analysis of 33 metaverse definitions revealed recurring conceptual features through both word frequency and thematic analysis. The most frequently occurring terms--metaverse, virtual, world, immersive, internet, physical, avatars, users, digital, and universe--reflect a dominant narrative positioning the metaverse as a digitally immersive ecosystem that blends virtual and physical realities. The patterns were consolidated into five principal thematic areas for the classification of definitions. Many definitions describe the metaverse as a convergence of these two domains [68; 69; 70], while others conceptualise it as a realm that transcends the physical world altogether [5; 48; 50; 55; 71]. It is often portrayed either as an extension of existing digital systems or as a distinct spatial layer beyond current internet frameworks. Across these interpretations, the Metaverse is frequently framed as the next generation of the internet [50; 56], offering users a more immersive, interactive, and socially engaging way to experience digital content. A key aspect of this immersive experience is the presence of three-dimensional virtual environments enabled by technologies such as augmented reality, virtual reality, mixed reality, and digital twins [57; 72; 73; 74; 75]. These spaces vary from realistic simulations of the physical world to imaginative, fantastical landscapes. Immersion is further supported through avatars, which serve as digital representations of users [69; 75; 76]. Avatars enable a sense of embodiment and personalised engagement, allowing users to navigate the Metaverse in ways that simulate physical presence. The metaverse is also widely defined as a communal environment, where avatars facilitate social interaction, collaboration, and the formation of persistent virtual communities [57; 54; 65]. These findings collectively illustrate an emerging consensus that defines the metaverse not merely as a technology stack, but as a socially immersive, persistent, and hybrid reality space that represents the evolving interface between humans, digital systems, and spatial computing. While the eight themes reflect detailed conceptual patterns in metaverse definitions, the five categorisation groups offer a broader synthesis, enabling comparative interpretation across dominant perspectives. Based on this thematic grounding, the 33 definitions were grouped into five conceptual categories to better capture their dominant orientations: conceptual and linguistic constructs (6 definitions), spatial-environmental design (9 definitions), technological orientation (3 definitions), economic and governance systems (6 definitions), and social and human interaction (9 definitions). Each definition was allocated to its predominant theme based on the contextual emphasis. In cases where a definition encompassed multiple themes, the most salient conceptual focus was used to determine its categorisation. * Conceptual and Linguistic Constructs (Table 4): These definitions consider the etymology or figurative meaning of the term \"metaverse\", frequently characterising it as an abstract or speculative idea, such as a realm \"beyond the universe\" or a new version of the internet. * Spatial-Environmental Design (Table 5): Within this theme, definitions predominantly describe the metaverse as an environment that is digitally created or immersive. These definitions often emphasise the importance of 3D spaces, virtual environments, and the blending or simulation of physical and virtual worlds. * Technological Orientation (Table 6): These concepts draw attention to the enabling function of technologies like blockchain, extended reality, augmented reality, virtual reality, and artificial intelligence. The metaverse is presented as a byproduct of the advancement of technology.