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.

Geological/geographical subcontinents

In plate tectonics, a small continental plate connected to a larger continental plate can be called a subcontinent. In this sense, the Indian subcontinent on the India Plate and the Arabian subcontinent on the Arabian Plate are recognized. The latter is not commonly called a subcontinent geographically because of lack of a geographical border and a variety in climate. Europe is just a peninsula since it is on the Eurasian Plate.

In geography, Europe is occasionally described as a subcontinent of Eurasia for its vast area. Likewise, the smallest continent Australia and the largest island Greenland are sometimes called subcontinents.

North America and South America are thought to be the two subcontinents of the continent of the Americas in some cases, because they are connected with an isthmus. Africa and Eurasia are sometimes considered to form the continent of Africa-Eurasia for the same reason. However, the Americas and Africa-Eurasia are usually called supercontinents, composed of continents.

Cultural subcontinents

The term the Indian subcontinent is used also culturally and politically. It includes India, Pakistan, and Bangladesh, and usually other South Asian countries too. While it is the standard name used internationally for the region, the term the Indo-Pak subcontinent is also used in Pakistan. The phrase the Subcontinent, used on its own in English, commonly means the Indian subcontinent.

Sometimes subregions of continents are dubbed subcontinents because their culture is so different from the rest of the continent, such as Central America and the Middle East.