The term VAST EXPANSE refers to a large area of land or water. It can be used to describe the vastness of the SEA, OCEAN, and ASIA. The crossword solutions for this term are SEA (3 letters), OCEAN (5 letters), ASIA (4 letters), and DEEPBLUESEA (11 letters). SEA and OCEAN refer to the large bodies of water that cover most of the Earth's surface, while ASIA is the world's largest continent. DEEPBLUESEA is a phrase that is often used to describe the vastness of the OCEAN.