The fact that vocabulum appears with far more frequency in Tacitus' texts than in any other author except for the encyclopaedists argues for his idiosyncratic usage of the term. This article argues that imperial discourse, nearly identical in structure and expression to that of the Republic but divorced from Republican connotations, provided an empty site where Roman fantasies of self-definition took strong hold, and that Tacitus uses vocabulum to indicate words and concepts that illustrate this process, particularly with reference to (...) representations of the foreign and the past. Such a discourse was congenial for the concentration of power in the hands of one person, as it no longer expressed the conflicting desires of a community engaged in public affairs, but collectivized the public desire for an image of Roman superiority. Thus Germany and the old Republican past were easily mythologized as what Rome desired to be, but feared it was not. Tacitus' use of vocabulum highlights the words in imperial discourse that betray the gap in the political unconscious between Romans' idea of themselves as masters of the Empire and as slaves to one ruler. Nor does he position himself as an outside observer of this process, but creates an experience of it for the reader through gaps and inconsistencies within his narrative. (shrink)