Great Russian language (Russian: Великорусский язык, Velikorusskiy yazyk) is a name given in the 19th century to the Russian language as opposed to the Ukrainian and Belarusian languages. For instance, Vladimir Dahl's monumental dictionary of the Russian language is titled The Explanatory Dictionary of the Living Great Russian Language.
By the standards prevalent in 19th-century Imperial Russia, many scholars did not distinguish between the Eastern Slavic languages spoken within the borders of the Russian Empire. The Eastern Slavic languages were claimed to be mutually intelligible, a position which has been called into question since. Great Russian, Little Russian (Ukrainian), and White Russian (Belarusian) were considered to be three dialects within the Russian language.
The name itself comes from the word Velikorossiya, or Russia Major, the term used in the Byzantine Empire and Russian Empire to distinguish the Russia proper from Malorossiya (Little Russia, now Ukraine) and Belorussia (White Russia, now Belarus).
The Great Russian, or just Russian, language was formed in the Late Middle Ages in the northern Russian principalities under heavy influence of Church Slavonic language. As compared to the Great Russian, other Eastern Slavonic languages were termed one-dimensional, because they lacked the stratum of high speech, derived from the Church Slavonic. For political reasons, the literary Russian language evolved under the significant influence of the Moscow dialect.