In the article Nikolaj Kostomarov as the Ukrainian Nationalist or Back to the Terminology there is the study of the terms, which were used in the historical works of N.Kostomarov about the history of the Ukraine. Particularly is studied the term Russian and South-Russian. It is shown that the terminology was formed under the pressure of the censorship and policy of the Russian Empire, including of the III District. At the free of censorship articles Kostomarov used terms Ukrainians and Ukrainian language. But even the compromised term South-Russian was used by Kostomarov to show the difference between Ukrainians and Russians.