The Old World consists of Africa, Europe, and Asia, regarded collectively as the part of the world known to Europeans before contact with the Americas. It is used in the context of, and contrast with, the New World (Americas).
In the context of archaeology and world history, the term "Old World" includes those parts of the world which were in (indirect) cultural contact from the Bronze Age onwards, resulting in the parallel development of the early civilizations, mostly in the temperate zone between roughly the 45th and 25th parallels, in the area of the Mediterranean, Mesopotamia, Persian plateau, Indian subcontinent and China.
These regions were connected via the Silk Road trade route, and they have a pronounced Iron Age period following the Bronze Age. In cultural terms, the Iron Age was accompanied by the so-called Axial Age, referring to cultural, philosophical and religious developments eventually leading to the emergence of the historical Western (Hellenism, "classical"), Eastern (Zoroastrian and Abrahamic) and Far Eastern (Hinduism, Buddhism, Confucianism, Taoism) cultural spheres.
The concept of the three continents in the Old World, viz. Asia, Africa, Europe goes back to classical antiquity. Their boundaries as defined by Ptolemy and other geographers of antiquity were drawn along the Nile and Don rivers. This definition remained influential throughout the Middle Ages (see T and O map) and the Early Modern period.
The Old World can be used for the half of the earth that is east of the 20th meridian west and west of the 160th meridian east. The center of the Old World is in the Indian Ocean at the intersection of the Equator and the 70th meridian east. The Old World includes Afro-Eurasia excluding Western Iceland, Eastern Russia and Cape Verde. The Old World also includes Eastern Greenland, Papua New Guinea, some of the Solomon Islands, most of Micronesia and most of Antarctica.
The mainland of Afro-Eurasia (excluding islands such as the British Isles, Japan, Sri Lanka, Madagascar and the Malay Archipelago) has been referred to as the World Island. The term may have been coined by Sir Halford John Mackinder in The Geographical Pivot of History.