Letters that make 9-11
1, 9 are letters that make '9-11'
Words within 9-11
11 are words within '9-11'
1, 9 are letters that make '9-11'
11 are words within '9-11'
1 possible definitions for '9-11'
Under this definition, 9-11 is a noun and has the following properties:
9/11, September 11, Sept. 11, Sep 11 have the same meaning as '9-11'
'9-11' can be considered an instance of terrorist attack.
'9-11' can be a category of terrorism, act of terrorism, terrorist act.