This study based on mat/met enclitic which attested in Old Turkic, Karakhanid Turkic, Modern Turkic Dialects, Anatolian dialects and magat which attested in old and modern Mongolian. Mat/met is related to Mongolian Magat by scholars. Enclitic Mat/met added to predicate noun, pronouns (personal, demonstrative, and interrogative) and to verb forms. Functions and meanings of mat/met is indicated and whole functions and meanings of mat/met interpreted by us in this article.