The 9/11 Attacks – Key Vocabulary

Vocabulary flashcards covering primary people, events, tactics, and security terms related to the planning, execution, and aftermath of the 9/11 terrorist attacks.

Soviet Invasion of Afghanistan (1979)

Military intervention by the USSR to support a pro-Soviet Afghan government, opposed by U.S., UK, Saudi Arabia, and Islamist rebels.

Osama bin Laden

Saudi-born militant who joined Afghan rebels, founded al-Qaeda, and masterminded the 9/11 attacks after turning against the Saudi-U.S. alliance.

Al-Qaeda

Militant Islamist organization created by bin Laden that declared holy war on the United States and planned the 9/11 attacks.

Jihad / Holy War

Religious struggle; used by al-Qaeda to justify violent action against perceived enemies of Islam, especially the U.S.

Gulf War (1991)

Conflict in which U.S.-led forces expelled Iraq from Kuwait; U.S. troop presence in Saudi Arabia afterward fueled bin Laden’s anger.

U.S. Military Bases in Saudi Arabia

Post-Gulf War American installations that bin Laden viewed as desecrating holy land and evidence of Saudi dependence on the West.

Exile of bin Laden

Saudi Arabia stripped bin Laden of citizenship in the 1990s, forcing him to Sudan and later Afghanistan, where he expanded al-Qaeda.

Kamikaze-Style Airplane Attack

Tactic of hijacking fuel-laden commercial jets and crashing them into targets to cause massive destruction, used on 9/11.

World Trade Center

Twin office towers in New York City symbolizing U.S. economic power; both were destroyed by hijacked Boeing 767s on 9/11.

Pentagon

Headquarters of the U.S. Department of Defense in Virginia, struck by a hijacked Boeing 757 on 9/11.

U.S. Capitol Building (Intended Target)

Seat of Congress in Washington, D.C.; believed to be the ultimate target of the fourth hijacked plane that crashed in Pennsylvania.

Muscle Hijackers

Fifteen al-Qaeda operatives trained to subdue crew and passengers, allowing pilot-hijackers to fly the planes into targets.

Box Cutter / Small Knife

Easily concealed blade permitted on pre-9/11 flights; used by hijackers to seize control of aircraft.

Pre-9/11 Airport Security

Minimal screening relying mainly on basic metal detectors; allowed small knives on board and provided limited cockpit protection.

Reinforced Cockpit Doors

Post-9/11 security upgrade; armored, bullet-resistant doors kept locked in flight to prevent hijacker entry.

Flight 93 Passenger Revolt

Action by passengers of the fourth hijacked plane that forced hijackers to crash in rural Pennsylvania, averting the attack on the Capitol.

Jet Fuel

Highly combustible aircraft fuel; large volumes on commercial jets amplified destructive power when planes were used as missiles.

Boeing 767 & 757

Large commercial aircraft models hijacked on 9/11; chosen for their range, fuel capacity, and availability on domestic routes.