The term helical form is a type of SPIRAL shape, which is characterized by a curved line that winds around a central point. It is often seen in nature, such as in the shape of a snail shell or a tornado. In architecture, helical forms are used to create staircases and other structures. In mathematics, helical forms are used to describe certain equations and functions. The crossword solution for helical form is 'SPIRAL, ' which is a six-letter word.