Complex sentence: The term in the sense of "a large landmass that is smaller than any of the usually recognized continents" can also refer to Greenland which is surrounded by salt-water and may therefore be considered a very large island or an unattached subcontinent.
Split into simpler sentences: The term in the sense of "a large landmass that is smaller than any of the usually recognized continents" can also refer to Greenland. It is a landmass surrounded by salt-water that is smaller than the recognized continents and may therefore be considered a very large island or an unattached subcontinent.