: any one of five levels of U.S. military defense readiness that are ranked from 5 to 1 according to the perceived threat to national security, with 1 indicating the highest level of perceived threat
It was determined that the secretary of Defense had the authority to declare DEFCON 3 on his authority.—Stephen A. Cambone
—sometimes used figurativelyDon't even mention the privatization of Social Security that will take Congress to DEFCON 1.—Sam Allis
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“DEFCON.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/DEFCON. Accessed 10 Jul. 2026.
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