The term 'Large Spiral Shell' can be broken down into two crossword solutions: TRITON (6 letters) and CONCH (5 letters). TRITON is a genus of sea snail, also known as a trumpet shell, which is characterized by its large size and spiral shape. The CONCH is a species of large sea snail, also known as the Strombus gigas, which is found in the Caribbean Sea and is known for its large, colorful spiral shell. Both of these species are popularly used in jewelry and decoration.