The article is devoted to the analysis of such an important methodological problem of terminography activity like the problem of metalanguage description. The achievements and failures of each linguistic paradigm are reflected in metalanguage. This is a complex part of the language, which focuses on implementation of a number of applied problems. First of all, it deals with the creating of Historical terminological dictionary of Ukrainian linguistic terminology. Theory of terminography, including linguistic, is based on specific system-creating terms, which are nominated by some units of appropriate metalanguage. The core of this metalanguage is linguistic terminology that is the core of functionally oriented formal language. Metalanguage includes also general vocabulary, nomenclature, professionalisms, professional slang and so on. However, the specific feature of terminography metalanguage is that it contains a special unit to indicate terminography concepts that haven’t been defined in the professional literature.
The article considers that the creator of metalanguage, language of special purpose, the author of a term is a scientist, a specific user of metadialect that’s why the terminological nomination is often determined by the peculiarities of language identity of the term’s author.
While studying the specific metadialect it is important not only to understand what the basis of terminological nomination is, but how and with the help of what communicative, cognitive strategies and tactics scientist "introduces" the created term, term notion, terminological definition into the scientific community, which sends its cognition to addressee.
Special attention is drawn to the branch of terminography called metalanguage that concerns macro- and micro- organization of vocabulary, architectonics of registry etc.
The importance of understanding the metalanguage as the main form of symbolic representation of scientific knowledge is determined.