Abstract
Background Although conspiracy theories are studied across multiple disciplines, their definition remains unsettled. Despite a substantial body of empirical research, definitions have not been systematically analysed, leaving it unclear how conceptual variation shapes research, methods, and findings. Methods Drawing on an original dataset of peer-reviewed publications, this study applies inductive qualitative content analysis to identify recurring dimensions along which academic definitions vary, including ontological assumptions, evaluative orientations, epistemic characterisations, constitutive features and scope. It further introduces a genealogical mapping of citation relationships to assess whether these dimensions structure more frequently reused definitions. Results The qualitative content analysis finds that most definitions describe conspiracy theories as explanations and adopt a neutral-descriptive stance, with intentionality, coalition, and secrecy forming a recurrent core constellation of constitutive features. The genealogical mapping shows that frequently reused definitions share these features but differ in their evaluative and epistemic characterisation. Conclusions Definitional diversity in conspiracy theory research is maintained through citations. Making definitional choices explicit and treating definitions as analytical tools rather than background assumptions can improve conceptual clarity, comparability, and cumulative research.