United Nations System
There are 15 members of the Security Council, consisting of five veto-wielding permanent members (China, France, Russia, the United Kingdom, and the United States) and 10 elected non-permanent members with two-year terms. This basic structure is set out in Chapter V of the UN Charter. Security Council members must always be present at UN headquarters in New York so that the Security Council can meet at any time.
United Nations Security Council veto power
The United Nations Security Council "veto power" refers to the power of the permanent members of the UN Security Council (China, France, Russia, United Kingdom, and United States) to veto any "substantive" resolution. A permanent member's abstention or absence does not prevent a draft resolution from being adopted. This veto power does not apply to "procedural" votes, as determined by the permanent members themselves. A permanent member can also block the selection of a Secretary-General, although a formal veto is unnecessary since the vote is taken behind closed doors.