What is "marchak"

The House of Marchak (Russian: МАРШАК) was founded by Joseph Abramovich Marchak, a young talented jeweler in 1878, in Kiev, then Russia. Considered one of the great competitors of Fabergé at the beginning of last century and sometimes called “The Cartier of Kiev”, the Marchak company employed 150 workers at the start of the Russian Revolution (1917). The name 'Marchak' (Russian: МАРШАК; Hebrew: מרש"ק)) is an acronym from the Hebrew expression Morenu Rabbi Shmuel Kaidanover, after the Kabbalah rabbi Aaron Samuel Kaidanover.