Definition of ground zero noun from the Oxford Advanced Learner's Dictionary

     

    ground zero

     noun
    noun
    BrE
     
    ; NAmE
     
    [uncountable]
     
    jump to other results
  1. 1the point on the earth’s surface where a nuclear bomb explodes
  2. 2Ground Zero the site of the Twin Towers in New York, destroyed on 11 September 2001 Culture The Twin Towers were two very tall office buildings in Manhattan, New York City, built by the Port Authority of New York and New Jersey in 1972-3 and housing offices of the World Trade Centers Association. For a short time they were the tallest buildings in the world. Each was 1 368 feet/417 metres high and had 110 floors. A terrorist bomb exploded in the garage of the building in 1993 killing six people and injuring more than a thousand. On September 11th 2001 the Twin Towers were both destroyed in another terrorist attack. Two planes crashed into the towers, and a short time later both towers collapsed. The area where the building used to be became known as Ground Zero, and is now the site of the National September 11 Memorial and Museum. see also September 11
  3. 3the beginning; a starting point for an activity
See the Oxford Advanced American Dictionary entry: ground zero