Krem·lin 
(krĕmlĭn)
(krĕmlĭn)n.
1. The citadel of Moscow, housing the offices of the Russian government and formerly those of the Soviet government. The outer walls of the compound date to the 1400s.
2. The government of Russia and formerly that of the Soviet Union.
3. kremlin The citadel of a Russian city.
[Obsolete German Kremelin, from Old Russian *kremlĭnŭ, separate, from kremlĭ, a separate place, citadel.]