The term 'Large Merchant Ship' can be summarized as an ARGOSY, which is a six-letter word. An ARGOSY is a large merchant ship that was used in the 16th and 17th centuries for trading purposes. It was typically a large, three-masted sailing vessel with a broad hull and a flat bottom. The ARGOSY was used to transport goods and passengers across the seas, and was often used by merchants to transport goods from one port to another.