Continent with other islands in the Pacific into one continent called Oceania. This divides the entire land surface of Earth into continents or quasi-continents. The ideal criterion that each continent is a discrete landmass is commonly relaxed due to historical conventions. Of the seven most globally recognized continents, only Antarctica and Australia are completely separated from other continents by the ocean. Several continents are defined not as absolutely distinct bodies but as ""more or less" discrete masses of land". Asia and Africa are joined by the Isthmus of Suez, and North and South America by the Isthmus of Panama. In both
Continent as "New Holland, an immense island, which some geographers dignify with the appellation of another continent" and the "Oxford English Dictionary" was just as equivocal some decades later. Antarctica was sighted in 1820 during the First Russian Antarctic Expedition and described as a continent by Charles Wilkes on the United States Exploring Expedition in 1838, the last continent identified, although a great "Antarctic" (antipodean) landmass had been anticipated for millennia. An 1849 atlas labelled Antarctica as a continent but few atlases did so until after World War II. From the mid-19th century, atlases published in the United States more commonly