This article offers a new conceptualisation of the meaning of norms in world politics. It starts from the observation that existing norm scholarship in International Relations has underestimated the role of ambiguity in the constitution of norm meaning. To address this shortcoming, we advance a conceptualisation that sees norm polysemy – the empirically observable plurality of norm meanings-in-use – as resulting from the enactment of inherently ambiguous norms in different contexts. By foregrounding norm ambiguity, this view offers a radically non-essentialist understanding of norm meaning, one that eschews any attempt to salvage final or ‘true’ meanings behind the polysemy of norms. Using empirical illustrations from different fields of contemporary global governance, we identify four mechanisms through which actors practically cope with the multiplicity of norm meanings that arises from norm ambiguity (deliberation, adjudication, uni- or multilateral fixation attempts, and ad hoc enactment) and outline their varying effects on the legitimacy and effectiveness of global governance. Based on this discussion, the article points to the normative implications of a radically non-essentialist conception of norms and suggests harnessing the positive potential of norm ambiguity as an ethically desirable condition that promotes human diversity and the plurality of global life.