Glossary for 9/11 and the War on Terror

On this page, you can find words that are particularly useful to know when studying 9/11, the War on Terror and related topics. Click each word for a full definition in English.

9/11 (s)


Refers to the terrorist attacks in the US that happened on September 11, 2001, coordinated by the Islamic terrorist group Al-Qaeda. The 9/11 attacks caused almost 3,000 deaths and damage estimated at around 10 billion dollars.

Al-Qaeda (s)


A militant Islamic fundamentalist group founded in Afghanistan in the 1980s. Al-Qaeda has a multi-national network and is described by international organizations as a terrorist group. The organization rejects foreign influence in Muslim countries.

black site (s)


A place, typically a facility of the US government where secret military operations are conducted. During the War on Terror, the US sometimes detained terrorist suspects in such places.

drone strikes (s)

Targeted missile attacks from an unmanned airborne vehicle. Most drone strikes have been carried out by the US military following 9/11 terrorist attacks. The drone strikes targeted countries like Afghanistan and Pakistan. Other countries that have drone-strike capacity are Israel, China, Iran, Italy, India, Pakistan, Turkey, and Russia.

enhanced interrogation techniques (s) 


A term used to describe ways in which American agencies tortured detainees through unacknowledged activities around the world such as at Guantanamo Bay and Abu Ghraib. These enhanced interrogation techniques were approved by the George W. Bush Administration during the War on Terror.

extremism (s)

Ideology representing extreme political or religious views that are outside what is considered acceptable in society. The term has been increasingly used to describe the religious views of Islamic terrorist groups such as Al-Qaeda or ISIL. 

fanaticism (s)

Describes extreme or unreasonable devotion, dedication, or enthusiasm, usually regarding a religious belief. Nowadays the term is often used as a synonym for extremism.

fundamentalism (s)

A form of a religion that respects the strict, literal interpretation of religious writings. 

Geneva Conventions (s)

Four treaties regarding the treatment of civilians and prisoners of war, designed to give these categories of people minimum protection and guarantee that their human rights are respected. The US was criticized for violating the Geneva Conventions when the Bush Administration started using torture to interrogate suspected terrorists.

Ground Zero (s)


A starting point or the center of an attack. The term is also used specifically to refer to the site where the World Trade Center used to be. Today Ground Zero has become a memorial to the victims of the 9/11 attacks. 

Guantanamo Bay (s)


An American military prison in Cuba, frequently abbreviated as GTMO. The detention camp was set up in 2002 by the George W. Bush Administration following the 9/11 attacks. The US has been often criticized and pressured to close down GTMO because some inmates there are detained indefinitely without trial and because of allegations of torture.

hijack (v)

To unlawfully take control over a vehicle in transit and impose a different destination or use it for one's goal. The 9/11 attacks were carried out by hijacking airplanes with civilian passengers.

intelligence agency (s)

State agency responsible for collecting and using information for national security or foreign policy and military goals. Intelligence agencies in the US were given extended powers after the 9/11 attacks to find those responsible and prevent similar events in the future.

ISIL (s)


Abbreviation for the Islamic State of Iraq and the Levant. ISIL is an Islamic terrorist organization and illegal state formed by terrorists in parts of Iraq and Syria. The group is known for extreme acts of violence and various terrorist attacks. Its name can be translated in various ways, including "Islamic State" (IS), “Islamic State in Iraq and Syria" or "Islamic State in Iraq and al-Sham" (ISIS), or the acronym Daesh formed from the group's previous name in Arabic - "al-Dawla al-Islamiya fil Iraq wa al-Sham".

jihad (s)


Arabic name for war or struggle against unbelievers. Extremist Muslims consider jihad a holy war and duty. Unbelievers are all those with other faiths, but also Muslims who are not respecting a fundamentalist belief.

mass surveillance (s)

The surveillance of the entire population or large groups of people, usually conducted by intelligence agencies. After 9/11, the use of mass surveillance has often been described as necessary to fight terrorism and to protect national security. However, the practice has also been criticized for violating privacy rights.

NSA (s)


Abbreviation for the National Security Agency in the US. The NSA is an intelligence agency responsible for gathering, analyzing, and using information for foreign policy purposes. Following the 9/11 attacks, the NSA played an important role in gathering intelligence about terrorist groups. In 2013, the NSA was the subject of an international scandal after contractor Edward Snowden leaked compromising documents about its mass surveillance activities.  

suicide bomber (s)

A violent attacker – typically a terrorist—who uses his death as a means to harm or destroy a target. Al-Qaeda attacks are often carried out by suicide bombers.

Taliban (s)


Fundamentalist Muslim militia which illegally took control of Afghanistan in the 1990s. The Taliban regime was overthrown by the US military intervention in Afghanistan after the 9/11 attacks. The movement is still waging war against the legal government in Afghanistan. The Taliban often collaborated with Al-Qaeda.

terror (s)


Violence carried out by a person, group, or organization aimed at frightening people and achieving a political goal. Since 9/11, the term has been used to refer to all terrorist groups in the world, particularly those in the Middle East.

terrorist (s)


Someone who uses extreme means to achieve political aims. Islamic terrorists hijacked planes in a suicide attack on key US buildings to frighten US citizens and express their rejection of the West.

The Patriot Act (s)


A legal Act signed into law in 2001 in the US, in response to the 9/11 attacks. The Act increased security controls, allowing police and state agencies to search people’s homes, phones, emails, etc. Many provisions of the Act were later declared unconstitutional.

waterboarding (s)


Interrogation method mimicking the experience of drowning. Such a technique has been used to interrogate alleged terrorist suspects after 9/11. It has been debated whether or not it counts as torture and whether it is illegal.

World Trade Center (s)


A huge business complex in New York City, US, including two landmark Twin Towers. The towers were completely destroyed in the 9/11 terrorist attacks.