In the specialized tourism vocabulary the main terms for designation of special interest tourism are not exactly defined and clearly distinct. This causes confusion when used in legal documents, strategies and business plans. This paper aims to analyze the conceptual issues in defining special interest tourism (SIT) and suggest ideas for their solving. It presents a common feature of the concept of SIT, makes a critical review of the achievements and problems in its development and formulates ideas and recommendations for a more precise definition of SIT. The methods of system analysis and scientific discussion, typology and ranking the types of tourism are used in the article, and as an essential tool – the conceptual definition. The main results and conclusions of the study concern the following issues: the lack of a clear demarcation of the content of close to SIT terms; the need for scientific discussion to formulate a clear and precise conceptual definition of the term special interest tourism by distinguishing the content of SIT from other types and forms of tourism; the construction of a terminology continuum for all major types of tourism; taking into account the different perspectives in defining SIT.