The subjects of the paper are hydrographic terms with the meaning ‘spring’
in Mongolian languages, their semantic and etymological features. The paper considers both derivative, and primary words. The words of both types can be combined with other words, thereby forming a large number of compound hydrographic terms. In this case some lexemes have a great variety of meanings, others are connected with a rather narrow range of meanings, i.e. have a minimum number of links of a semantic chain. The determination of the built-in possibilities of the Mongolian languages for the forming of terminological systems is not only of national, but also of international significance because the process of nomination displays universal features. Hydrographic terminology is a reliable source for identifying the processes of formation and development of the Mongolian languages.