Liquid Democracy (LD) is a recent phenomenon that could radically affect our understanding of democracy. Yet, there remains significant semantic confusion surrounding this concept, and researchers in the social sciences, as well as in political theory, currently lack a general definition that is broadly accepted as a standard reference. Therefore, this article addresses the following question: What is LD and how can we best define it? Following a classical, semantic approach to concept formation in the tradition of Giovanni Sartori and John Gerring, the article advances a new, minimal definition: LD is a decision‐making scheme characterized by liquidity—that is the systemic and flexible mix of direct and representative democracy—and essentially based on the principles of voluntary delegation and proxy voting. This definition can serve as a starting point from which further theoretical and normative studies of LD could be conducted in the future.