Subcontinent
A subcontinent is a large part of a continent. There is no agreement on what constitutes a subcontinent. Generally, however, a subcontinent is split from the rest of a continent by something like a mountain range, or by tectonic plates.India, Pakistan, and Bangladesh, and sometimes Nepal and Bhutan are together often said to make up the Indian subcontinent or just the subcontinent (Being split here by the Himalayas). Occasionally, Europe is described as a subcontinent of Eurasia.
In some cases, North America and South America are believed to be two subcontinents of the continent of the Americas. This is because they are both part of one landmass. In another related cases, the supercontinent of Eurasia, or even Eurasia-Africa can be subdivided into Africa, Asia and Europe for the same reason as the last.
Sometimes subregions of continents are dubbed subcontinents because their culture is so different from the rest of the continent. For example Central America and the Middle East.
See also: plate tectonics