Volcano Vocabulary List & Definitions provides key terms related to volcanoes including: disaster which refers to a catastrophic event often resulting in loss of life or property; dormant meaning not currently active; erosion as the gradual process of being worn away by natural forces; eruption as the bursting forth of material from a volcano; lava as molten rock that flows from an erupting volcano; and ash as the fine material thrown from an erupting volcano. Additional terms are magma as the molten material under the earth's crust where igneous rock forms; pumice as a light volcanic glass used for cleaning; summit referring to the topmost part; vent as an opening or outlet; and crater denoting an opening