The central role of terms in science communication is based on the fact that they designate and identify key objects and subject matters of an academic discipline. As will be shown, the traditional or general theory of terminology has defined the understanding of terms for a long time, specifying that a term should refer to one mental concept only, which in turn is linked to a specific object in a univocal manner, that a term should be monosemous and must be understood regardless of the context. The establishment of hierarchically ordered terminological systems would thus be a warrant for smooth and trouble-free communication between scientists, the theory assumes. One look at the use of terminology in any single discipline shows, however, that the validity of these principles is rather limited, and there are both concurring and polysemous expressions in every scientific field. Moreover, the concept of meaning advocated in traditional terminology theory is met with criticism by proponents of cognitive linguistics and pragmatics. More recent approaches such as socioterminology and the study of terms in specialized language research focus on various aspects of term usage. These include, first of all, mapping out the knowledge organization involved in the use of terms and a new conception of terms as prototypes or frames, e. g. in socio-cognitive approaches, and, secondly, the social function of terms such as added prestige for users of particular terms, or the semantic struggles over terms; a third line of research explores how terms have been used in different academic disciplines, in different text types and at various moments in time. In recent research, processes of terminologisation and de-terminologisation have increasingly become the focus of attention.