noun
a surprise attack involving the deliberate use of violence against civilians in the hope of attaining political or religious aims
• Hypernyms: ↑surprise attack, ↑coup de main, ↑terrorism, ↑act of terrorism, ↑terrorist act
• Instance Hyponyms: ↑9/11, ↑9-11, ↑September 11, ↑Sept. 11, ↑Sep 11
Useful english dictionary. 2012.