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 the tectonic plates.
India, Pakistan, and Bangladesh are together often said to make up the Indian subcontinent or just the subcontinent (Being split here by the Himilayas. Occasionally, Europe is described as a subcontinent of Eurasia.
See also: plate tectonics