1A characteristically Russian word, phrase, or idiom, especially when used in another language.
2As a mass noun: the use of Russianisms or Russianized language.
3Attachment to or support for Russia and Russian political or cultural ascendancy.
4Russian character, spirit, or quality.
5A Russian characteristic or custom.
6Soviet communism as practised by the Russians.
Early 19th century. From Russian + -ism. Compare slightly later Russism and the foreign-language nouns cited at that entry.