The term BIG SHIP can be broken down into two crossword solutions: ARK (3 letters) and LINER (5 letters). An ARK is a large vessel, typically one that is built for religious purposes. It is most famously associated with Noah's ARK from the Bible. A LINER is a large ship that is used for transporting passengers and cargo on regular routes. Liners are often used for long-distance travel, such as between continents. Both arks and liners are considered to be big ships.