Disarmament is when a country reduces the number of weapons it has, or makes its army, navy, or air force smaller. News and politics use it constantly. Nuclear disarmament is the long argument about having fewer nuclear bombs, or none. Though actually, the word does not always mean “no weapons at all.” It often means “fewer than before,” or “this kind of weapon, not that kind.” Two countries can sign a disarmament deal and still keep large armies. People also stretch it a little for groups laying down guns after a war, but the home of the word is states and treaties, not a person putting a knife away.