Cheka
/ˈtʃekə/- an organization under the Soviet regime for the investigation of counter-revolutionary activities. Formed in 1917, it was replaced by the OGPU in 1922.契卡（苏维埃政权调查反革命活动的组织。1917年成立, 1922年被格伯乌代替）。
词源
Russian， from che, ka, the initial letters of Chrezvychaīnaya komissiya 'Extraordinary Commission （for combating Counter-revolution， Sabotage， and Speculation） '.