The aim of this article is a conceptual historical analysis of parliamentarism with a focus on intra-parliamentary concepts, their origins, changes and the disputes around them. The formation of a distinct parliamentary vocabulary helps us to distinguish parliaments from other assemblies. Neither conceptual nor parliamentary histories, however, have directed any attention to the concepts by which parliaments operate for conducting and regulating their deliberations, using ordinary language concepts but giving them a specific parliamentary meaning. The procedural tracts for Westminster from the late sixteenth to the early twentieth century provide strategic sources for the politics and history of intra-parliamentary concepts. In this article, four types of parliamentary concepts of action and debate are distinguished, namely those referring to parliamentary moves, to parliamentary order, to parliamentary time and to parliamentary agenda. They refer to different aspects of parliamentary debates; they have different histories in terms of intentional or tacit conceptual changes, and explicit disputes around the concepts. In terms of classical rhetoric, moves refer to elocution, their regulation by order and time to two forms of disposition, and the agenda to the invention. The opposition between ‘parliamentary’ and ‘unparliamentary’ uses of concepts can be understood in the sense of Reinhart Koselleck's distinction between symmetric and asymmetric use of political concepts.