This Article analyses the classical and modern approaches to the definition of the concept of trust, considering its expansion in countries that traditionally did not recognize this institution. Specifically, the Article contains the assessment of definitions given to the concept of trust, that are currently being offered for use in European private law, which is some kind of «compromise» for the legal systems functioning in each of the European Union member states. Based on the results of the analysis the author proposes her own definition of the concept of trust which, from her point of view, should meet the current needs of social relations’evolution.