noun

• (communism, Marxism) The governing council and chief policymaking body of the Communist Party of the Soviet Union and other Marxist-Leninist political systems.
• (by extension, politics, sometimes derogatory) A senior governing or policymaking body in a political or other organization, generally consisting of members who are either appointed by the party in control of the organization, or who attain membership through their personal political affiliations; an inner circle.
  "They were the people who surrounded Biden who were the true believers: Ricchetti, Donilon, etc. The Politburo would argue that the decisions were always fine and sound and never problematic."

name

• (metonymic) The senior leadership of the Soviet Union, or that of the People's Republic of China.