commissariat n.

late 14c., "one to whom special duty is entrusted by a higher power," from Medieval Latin commissarius, from Latin commissus "entrusted," past participle of committere (see commit).

Originally especially ecclesiastical, "one who performs a bishop's duties in distant places or when he is absent;" the military sense of "official in charge of supply of food, stores, and transport" dates to late 15c. Hence "storeroom" (1882, U.S. military), especially for selling articles to persons engaged in a particular line of work,  and then "dining room in a larger facility" (1924, American English), such as a movie studio.

in a Russian context, "representative appointed by a soviet and responsible for political indoctrination," 1918, from Russian komissar, from German Kommissar "commissioner," from French commissaire, ultimately from Medieval Latin commissarius (see commissary). Earlier in English it meant "commissary" (1640s), from the French word, which itself was used in English from 1753.