The United Nations Security Council "power of veto" refers to the veto

Veto

A veto, Latin for "I forbid", is the power of an officer of the state to unilaterally stop an official action, especially enactment of a piece of legislation...

 power wielded solely by the five permanent members of the United Nations

United Nations

The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

 Security Council

United Nations Security Council

The United Nations Security Council is one of the principal organs of the United Nations and is charged with the maintenance of international peace and security. Its powers, outlined in the United Nations Charter, include the establishment of peacekeeping operations, the establishment of...

 (China

People's Republic of China

China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...

, France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

, United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, and United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

), enabling them to prevent the adoption of any "substantive" draft Council resolution, regardless of the level of international support for the draft. The veto does not apply to procedural votes, which is significant in that the Security Council's permanent membership can vote against a "procedural" draft resolution, without necessarily blocking its adoption by the Council.

The veto is exercised when any permanent member—the so-called "P5"—casts a "negative" vote on a "substantive" draft resolution.