The term 'Bounding Main' is a nautical phrase that refers to the OCEAN, and is often used in SEA shanties. The crossword solutions for this term are OCEAN (5 letters), ASEA (4 letters), SEA (3 letters), and OPENSEA (7 letters). OCEAN is the largest body of water on Earth, while ASEA and SEA refer to smaller bodies of water. OPENSEA is a term used to describe the open OCEAN, which is the vast expanse of water between continents.