In France, today's political discourse on research, education and professional training is fraught with the words "interdisciplinary", "multidisciplinary", "cross-disciplinary" or "trans-disciplinary". These words comprise the latest trend in the vocabulary used in these fields, despite the fact that the academic world remains strongly organised along disciplinary lines (Foucault, 1975, 1997.) Currently, academic disciplines constitute a model of organisation. Although everyone today uses this vocabulary, no one actually knows what the words "inter-disciplinary" or "multidisciplinary" stand for. Epistemological debate (Gusdorf, Sinaceur, 1983; Klein, 1990…) points to the following paradox: although this vocabulary is regularly used in many academic fields, it has yet to be clearly defined. How can the multiple uses of this particular vocabulary be explained? Is this vocabulary merely a form of speech or does it actually refer to an innovative system of organisation in research? This paper aims to demonstrate that this vocabulary plays a real function in the organisation and development of collective activities and academic research in French research institutions such as the CNRS, INRA, INRIA, INSERM.I rapidly introduce some of the components of my theoretical framework. Research activities are structured along in academic disciplines. Disciplines produce paradigms. Kuhn (1983) gives the following definition of a paradigm: an area of action driven by specific rules and customs. It is used to describe what is considered to be "good", "useful" for the activity, for research. It's a model for "best action". Thus, disciplinarity comprises both a context of action and a culture of action (internal focus and external focus). This constraining paradigm brings to actors learn from work situations and to build strategies of action in order to resolve the human or material problems they come across. They are able to construct a kind of personal culture which works as a "toolkit" (Swindler, 1986; Sainsaulieu, 1987, 1988; Crozier, Friedberg 1977). Our hypothesis is that the vocabulary of "interdisciplinarity" is a trace of this personal culture in response to the main disciplinary culture of academic action.Our corpus focuses more specifically on the CNRS's activity reports since 1953 and on the political discourse concerning research policies. Moreover, we interviewed 21 researchers in various academic fields (biology, physics, mathematics, computer science, chemistry) in order to understand how they referred to interdisciplinary work and how they comprehended it.I focus my study on the discourse concerning "interdisciplinarity". My study did not focus directly on actual research activities but rather on the words researchers used to describe their activities. I believe that the discourse on "interdisciplinarity" points to a new culture of action, contrary to academic culture.After analysing the discourse of researchers, we were able to distinguish three different types or three different models of interdisciplinary activities.The first model is based on a disciplinary conception of activities. Researchers are experts, specialised in one particular subject of their discipline, and they exchange with other experts, specialized in an other subject. This type of collaboration is useful to both, albeit in different ways and for different reasons.The second model is based on a transversal conception of activities. This point of view tends to regard academic disciplines as useless conventions. The emphasis lies on scientific issues. Collaboration serves the researcher's mobility (between several disciplines). He becomes polyvalent.The third and last model of interdisciplinary activity is based on a utilitarian conception of science. Collaboration is used to answer social demands. The interest of research lies in its social uses.Moreover, in the discourse of researchers we can observe that interdiciplinarity is seen as a positive value for action as opposed to the more conventional disciplinary point of view/stance (negative action). Up to a certain point, all three types of activities and the positive value can be linked to an innovative culture of action. It does not put in question the actual organisation of science along disciplinary lines, it puts in question the perimeter of disciplines and the way disciplines are used. However, this culture of actions still remains a representation (it is yet to turn into an act).BARBIER, Jean-Marie, article : Sémantique de l'Action et Sémantique de l'Intelligibilité de l'action, in MAGGI Bruno (sous la dir.), Manière de Penser, Manière d'Agir en Education et Formation, PUF, 2000. COZIER Michel, FRIEDBERG Ehrard, L'acteur et le système; éd.Seuil, Paris, 1977. FOUCAULT Michel, L'Archéologie du Savoir, Gallimard, biblio. des Sciences humaines, Paris, 1969. FOUCAULT Michel, Surveiller et Punir, coll. Tel, éd. Gallmimard, Paris, 1975. FOUCAULT Michel, Il faut défendre la société, Cours au Collège de France, 1975-1976, Hautes Etudes, Gallimard, Seuil, Paris, 1997. FOUCAULT Michel, L'ordre du discours, Leçon inaugurale au collège de France prononcée le 2 décembre 1970, Gallimard, Paris, 1971.KUHN Thomas K., La Structure des Révolutions Scientifiques, Champs Flammarion, éd. 1983 SAINSAULIEU Renaud, L'identité au Travail, Références, Presse Universitaire de la Fondation nationale des Sciences Politiques, éd. 1988, Paris SAINSAULIEU Renaud, Sociologie de l'organisation et de l'entreprise, Presse de la fondation nationale des sciences politiques & Dalloz, Paris, 1987 SAINSAULIEU Renaud, Sociologie de l'organisation et de l'entreprise, Presse de la fondation nationale des sciences politiques & Dalloz, Paris, 1987 SWIDLER Ann, Culture in Action : Symbols and Strategies in American Sociological Review, 1986, vol.51, (April: 273-286)