9/11

or 9-11

[ nahyn-i-lev-uhn ]

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.

9-11

1. See September 11 attacks .

Word History and Origins

Origin of 9/11¹

First recorded in 2000–05