The study analyzes the definitions of terms that name the main regulatory documents for top-level medical personnel: “clinical recommendations”, “clinical guidelines”, “diagnostic and treatment protocol”. The article compares the terminological phrases with the keywords “recommendations”, “management” and “protocol”, multicomponent units that name specific varieties of these documents. It was revealed that a large number of syntagmatic connections of the main term and its derivatives (attributive and substantive) explains the coexistence of many derived units, which complicates the professional communication process. All terms are divided into semantic groups in accordance with the semantics of dependent words. The studied regulatory documents are characterized by a common goal, functions, are similar in terms of composition and text structure, though they belong to different types of documentation. An analysis of the definitions showed that the “clinical recommendations”, “clinical guidelines” and “diagnostic and treatment protocol” have a different set of relevant (constitutive, basic) features of the document. A comparison of the definitions of the three main types of documents — recommendations, guidelines and protocol — showed that these terms can not be called either synonyms or quasi-synonyms, since they are characterized by belonging to the same part of speech, partial coincidence of valency, but do not match in their interpretation. These terms can be used in different conditions: recommendations — in case of dispositive use, guidelines — in the case of imperative compliance with the rules for using the document, protocols — in case of adaptation of the first two documents to medical practice of specific medical institutions, in hospital practice.