It refers to the formal authorization or consent given by Congress for specific actions taken by other branches or entities within government. In relation to military action, it means that Congress must approve before engaging in significant conflicts or wars.
Related terms
War Powers Act: A law that requires the President to consult with Congress and seek approval for military actions.
Declaration of War: The formal act by which a nation's legislative body declares a state of war exists between itself and another country.
Authorization for Use of Military Force (AUMF): A resolution passed by Congress that grants the President authority to use military force.