The term 'volcano shape' can be described by the crossword solution 'CONE, ' which is a four-letter word. A volcano is a geological landform created by the eruption of molten rock from the Earth's interior. The most common type of volcano is a CONE-shaped structure, with steep sides and a crater at the summit. This type of volcano is formed when lava and ash are ejected from the vent in the Earth's surface.