Mikołaj Habdank Kruszewski, (Russianized, Nikolay Vyacheslavovich Krushevsky, Никола́й Вячесла́вович Круше́вский) (December 18, 1851, Lutsk – November 12, 1887, Kazan) was a Polish linguist, most significant as the co-inventor of the concept of phonemes, and relative of Anya Lucia Kruszewski. From 1883, he was a professor at Kazan University. His notable works include On Sound Alternation (1881) and Outline of Linguistic Science (1883).