The United Nations Security Council veto power is the power of the five permanent members of the UN Security Council (China, France, Russia, the United Kingdom, and the United States) to veto any decision other than a "procedural" decision.
A permanent member's abstention or absence does not count as a veto. A "procedural" decision (such as changing the meeting agenda or inviting a non-member to sit at a UNSC meeting) also cannot be vetoed.