Definition

1. Proper noun:
   • September 11, 2001: The specific date of a coordinated series of terrorist attacks carried out against the United States, involving the hijacking of commercial airliners which were then crashed into significant targets.

Usage

• Proper noun:
  • The term "Sept. 11" is used to refer to the events of that day as a singular historical moment. It is often used attributively to describe things related to the attacks.
  • Example: The world changed after Sept. 11.
  • Example: Sept. 11 memorials are held annually.

Advanced Usage

• "Post-Sept. 11 world": Used to describe the geopolitical and social era following the 2001 attacks.
  • Example: Aviation security was completely overhauled in the post-Sept. 11 world.
• "Sept. 11-style attack": Used to describe a terrorist attack method similar to the 2001 hijackings.
  • Example: Intelligence agencies work to prevent any Sept. 11-style attack.

Variants and Related Words

• 9/11: The most common numerical variant for "September 11." It is synonymous and more frequently used in everyday language.
  • Example: The 9/11 attacks targeted New York and Washington.
• September 11 attacks: The full descriptive term for the events.
• 9/11 attacks: A common descriptive term.

Synonyms

• 9/11: The primary synonym.
• The September 11 attacks: A more formal descriptive synonym.
• The 2001 attacks: A contextual synonym when the year is understood.

Related Phrases

• Ground Zero: Refers specifically to the World Trade Center site in New York City after the attacks.
  • Example: The Sept. 11 memorial is located at Ground Zero.
• War on Terror: A term for the international military campaign launched in response to Sept. 11.
  • Example: The War on Terror began after Sept. 11.

Noun

1. the day in 2001 when Arab suicide bombers hijacked United States airliners and used them as bombs