Asia is the largest and most populous continent or region, depending on the definition. It covers 8.6% of the Earth's total surface area, or 29.4% of its land area, and it contains more than 60% of the world's human population.The word Asia entered English, via Latin, from Ancient Greek ?s?a. This name is first attested in Herodotus, where it refers to Anatolia; or, for the purposes of describing the Persian Wars, to the Persian Empire, in contrast to Greece and Egypt. Herodotus comments that he is puzzled as to why three women's names are used to describe one land mass, stating that most Greeks assumed that Asia was named after the wife of Prometheus but that the Lydians say it was named after Asias, son of Cotys who passed the name on to a tribe in Sardis.Asia is traditionally defined as part of the landmass of Africa-Eurasia – with the western portion of the latter occupied by Europe – lying east of the Suez Canal, east of the Ural Mountains, and south of the Caucasus Mountains and the Caspian and Black Seas.