Antarctica means the land areas (including ice shelves and the space above them) and the marine areas (including the sea below the ice shelves) which are located south of 60° South Latitude*.
*:Section 1, Article 3 of Law Relating to Protection of the Environment in Antarctica
In some cases Antarctica indicates the area south of the Antarctic Convergence along 50-60° South Latitude.
The Antarctic Circle is the area south of 66.5° South Latitude.