This article examines and summarizes different viewpoints on the notion of the “term” in order to answer the specific questions which arise when compiling a specialized dictionary. The author gives an overview of the answers found in current theoretical models as well as those that can be inferred from the examination of existing specialized dictionaries. This overview reveals that approaches are varied and often incompatible. Furthermore, some questions remain unanswered when considering the problem of selecting terms in a dictionary. The author formulates his own definition which in is accourdance with the objectives defined and examines its methodological consequences.