in early geologic time, a “supercontinent” that incorporated almost all of Earth's landmasses and covered nearly one-third of Earth's surface. It was surrounded by a global ocean called Panthalassa. Pangea was fully assembled by the Early Permian (Permian Period) Period, some 270 million years ago. It began to break apart about 200 million years ago, during the Early Jurassic (Jurassic Period) Period, eventually forming the modern continents and the Atlantic and Indian Oceans. The existence of the Pangean supercontinent was first proposed in 1912 by the German meteorologist Alfred Wegener (Wegener, Alfred Lothar) as a part of his theory of continental drift. Pangea's name is derived from the Greek pangaia, meaning “all the Earth.”

During the Early Permian, the northwestern coastline of the ancient continent Gondwana collided with and joined the southern Euramerican continent. With the fusion of the Angaran part of Siberia to this combined landmass during the middle of the Early Permian, the assembly of Pangea was complete. Cathaysia, a landmass comprising both North and South China, was not incorporated into Pangea. Rather, it formed a separate, much smaller, continent within the global ocean, Panthalassa.

During Earth's long history, there probably have been several Pangea-like supercontinents. The oldest of these supercontinents is called Rodinia and was formed during Precambrian (Precambrian time) time some 1 billion years ago. Another Pangea-like supercontinent, Pannotia, was assembled 600 million years ago, at the end of the Precambrian. Present-day plate motions are bringing the continents together once again. Africa has begun to collide with southern Europe, and the Australian plate is now colliding with Southeast Asia. Within the next 50 million years, Africa and Australia will merge with Eurasia to form a supercontinent that approaches Pangean proportions. This episodic assembly of the world's landmasses has been called the supercontinent cycle or Wegenerian cycle, in honour of Alfred Wegener.