The article presents a morphemic account of transcategoriality, with detailed illustrations (e.g. English but and even, French encore, tout, meme, Latin to French morpheme /tant/) of the approach. After making explicit the paradigmatic differences between exoskeletal and endoskeletal approaches, and showing that ultimately it can be summarized in terms of existence or not of grammar-free morphemes becoming lexemes through grammatical and contextual insertion, it turns to the issue of knowing what an exoskeletal non-categorial meaning can be. It introduces at this stage the notion of fractality, before making explicit and detailing the method which allows isolation of a morpheme’s indicational semantics. The whole approach is finally illustrated with the study of the whole distribution of French /tant/, first semantically in synchrony before extending the tests to Latin data, showing that polysemy, transcategoriality and plurisemy are various forms of the same issue.