EN
The aim of the paper is to analyze the scope of the following terms: język specjalistyczny, język specjalny, język fachowy, język profesjonalny, język zawodowy, profesjolekt, technolekt (language for special purposes, specialist language, special language, expert language, professional language, occupational language, professiolect, technolect), which are used interchangeably in the Polish linguistic literature even though their denotations are not the same. The semantic (in)compatibility of the above terms was investigated in the following stages: (1) explaining the meaning of the expressions without their theoretical context, i.e. the analysis of the meanings of specific components of the terms as established in general Polish; (2–3) interpretation of explanations and specifications functioning in dictionaries containing linguistic terminology and in theoretical studies; (4) formulating a proposal of distinguishing the concepts by defining the scopes of the terms and the relationships between them.