September 11th refers to the date when four coordinated terrorist attacks were carried out by al-Qaeda against targets in the United States. The attacks resulted in significant loss of life and caused widespread fear and shock across America.
Related terms
World Trade Center (WTC): Twin towers located in New York City that were targeted during the September 11th attacks and subsequently collapsed.
Osama bin Laden: The founder and leader of al-Qaeda who orchestrated the planning of the September 11th attacks.
Flight 93: One of four planes hijacked during the September 11th attacks; passengers aboard this flight fought back against the hijackers, resulting in it crashing into a field instead of its intended target.