The process of approximation of Ukrainian legislation with the EU acquis requires a clear definition of the scope and content of the concept of «transposition». The purpose of this article is to clarify relationship of the notion «transposition» in the field of EU external relations law with the concepts of «adaptation», «approximation», «harmonization», «unification» and others. Transposition of law is related to the trends and forms of harmonized legal development of states in international and national law. The notion of the «transposition» of law relates to the notions of «adaptation», «convergence», «harmonization» and «unification» as a general and special. In the field of EU external relations the transposition of law is shown as a process, which leads to the adaptation, convergence, harmonization and unification of EU law with ultimate objective of exporting the EU acquis into legal systems of third countries. Material and procedural means of the export of the EU acquis into legal systems of third countries are specific features of the transposition of law in the field of EU external relations.