9/11 Definition
 nīnēlevən, nīnilevən 
    noun
  
 September 11, 2001, the date on which two hijacked airliners were flown into the World Trade Center in New York City and another into the Pentagon. A fourth hijacked airliner crashed in open land in Pennsylvania.
 American Heritage 
An event comparable to 9/11.
 Wiktionary 
    pronoun
  
 The attack itself.
 Wiktionary 
    symbol
  
 The cardinal number nine.
Wiktionary 
Other Word Forms of 9/11
Noun
Singular:
 9/11Plural:
 9-11sOrigin of 9/11
- From the date September 11 written in numbers according the format used in the United States, which puts the month before the day. - From Wiktionary 





