9/11

American  

[nahyn-i-lev-uhn] / ˈnaɪn ɪˈlɛv ən /

Or 9-11

1. September 11, 2001: the day on which Islamic terrorists, believed to be part of the Al-Qaeda network, hijacked four commercial airplanes and crashed two of them into the World Trade Center in New York City and a third one into the Pentagon in Virginia: the fourth plane crashed into a field in rural Pennsylvania.

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9-11 Cultural  

1. See September 11 attacks.

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Etymology

Origin of 9/11

First recorded in 2000–05

Example Sentences

Created in the wake of 9/11, it encompasses most of the agencies that keep the U.S. secure from both external attack and internal disruption.

From The Wall Street Journal

But these lines of thought avoided the truth made plain by 9/11.

From The Wall Street Journal

On the institutional front, it is time to re-examine the Department of Homeland Security, which was created in the wake of 9/11 to fight terrorism.

From The Wall Street Journal

She was a junior in high school when the 9/11 attacks devastated her community and the nation and ultimately led her to a decade of service in the Special Operations community.

From Salon

After 9/11, for example, we celebrated the return of baseball as a valued respite from the tragedies we were dealing with.

From Los Angeles Times