The term 'spiral formation' can be described by the 6-letter word 'VOLUTE'. A VOLUTE is a spiral-shaped structure, often found in architecture and engineering. It is a curved structure that spirals around a central point, and is used to provide support or decoration. In architecture, volutes are often seen in columns, staircases, and other decorative elements. In engineering, volutes are used to increase the efficiency of pumps and turbines.