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• 9/11
  9/11

  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.
• 9-11
  9-11

  See September 11 attacks.

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

See Examples For:

9/11 9-11

“Everything I thought I wanted to say about war in ‘Devil’s Backbone’ seemed obsolete, because we had gone through 9/11 and the world had changed,” Del Toro recalls.

From Los Angeles Times ● Oct. 9, 2026

Most Americans are old enough to remember life before 9/11, when public spaces were far less protected.

From The Wall Street Journal ● Oct. 9, 2026

In an interview with CNN on Wednesday evening, Netanyahu said the stabbed pilot, passengers and second crew had "managed to prevent a 9/11 disaster".

From BBC ● Oct. 3, 2026

He worked on the Pentagon renovation after 9/11.

From Los Angeles Times ● Oct. 3, 2026

“Is that true? Seems like a girl who’d go to the”—Pop swallows; he doesn’t say the 9/11 Memorial—“is old enough.”

From "Towers Falling" by Jewell Parker Rhodes

Time is more pressing for the hope of rescheduling Bahrain in the gap that currently exists between Azerbaijan on 24-26 September and Singapore on 9-11 October.

From BBC ● Jul. 14, 2026

The swap was part of a three-day ceasefire that the two sides had agreed to from 9-11 May, which covered Russia's scaled-down Victory Day parade in Moscow.

From BBC ● May 15, 2026

Unions called the February 9-11 strike, accusing the authorities of ignoring warnings about the safety of infrastructure and failing to invest enough in the network.

From Barron's ● Feb. 9, 2026

The union will vote on whether to approve the agreement July 9-11.

From Los Angeles Times ● Jul. 4, 2025

In the wild, a female will take between 5-7 years to mature whereas males will take 9-11 years.

From Free from School by Rahul Alvares