Bezuidenhout, RiaanNel, WynandMaritz, Jacques2023-04-102023-04-102022-06-30Bezuidenhout, R., Nel, W., & Maritz, J. M. (2022). Defining decentralisation in permissionless blockchain systems. The African Journal of Information and Communication (AJIC), 29, 1-24. https://doi.org/10.23962/ajic.i29.142472077-7213 (online version)2077-7205 (print-on-demand version)https://doi.org/10.23962/ajic.i29.14247The term decentralised as a description of the architecture, operation, and governance of permissionless blockchain systems has become ubiquitous. However, in these contexts, the term decentralised has no clear definition. Blockchain ecosystems are complex, and thus it is essential to address confusion among stakeholders about their nature and promote understanding of the intentions and consequences of their implementation. This article offers a theoretical definition of the term decentralised in the context of permissionless blockchain systems. It is proposed that five inextricable and interconnected aspects are required, at a minimum, to warrant a claim that a permissionless blockchain system is decentralised. These aspects are disintermediation, a peer-to-peer network, a distributed blockchain data structure, algorithmic trust, and open-source principles. The relationship between the five aspects is discussed, and it is argued that decentralisation is not binary but exists on a spectrum. Any variation in one or more aspects may impact the system’s decentralised nature as a whole. The researchers identify areas where further investigation in this field is required and propose instances where the knowledge garnered may be used.enCopyright (c) 2022 Riaan Bezuidenhout, Wynand Nel, Jacques Maritz. This article is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence: https://creativecommons.org/licenses/by/4.0Articlehttps://doi.org/10.23962/ajic.i29.14247