what is significance of the word subcontinental?

Answer 1

a sub continent means:
A large landmass, such as India, that is part of a continent but is considered either geographically or politically as an independent entity.
also A large landmass, such as Greenland, that is smaller than a continent

Therefore significance of the word subcontinental lies in grouping the areas which have common climatic as well as physical chracterstics.
Also they have common cultural and political threads between them

For eg

The term the Indian subcontinent is used also culturally and politically. It includes India, Pakistan, and Bangladesh, and usually other South Asian countries too. The region has wide geographical variations like desert, plateau, rainforest, mountains and a myriad of languages, races and religions.

Sometimes subregion 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.

Answer 2

A region is known as a subcontinent because its geography and geology are distinct from the rest of the continent. So "subcontinental" signifies that it is a large region with distinct properties, particularly in geography and geology. In the example cited below, there is a whole region of the planet that was at one time actually separate from the rest of the continent.