ETYM Italian lava lava, orig. in Naples, a torrent of rain overflowing the streets, from Italian and Latin lavare to wash. Related to Lave.
Rock that in its molten form issues from volcanos.
Molten rock (usually 800–1100şC/1500–2000şF) that erupts from a volcano and cools to form extrusive igneous rock. It differs from magma in that it is molten rock on the surface; magma is molten rock below the surface. Lava that is high in silica is viscous and sticky and does not flow far; it forms a steep-sided conical volcano. Low-silica lava can flow for long distances and forms a broad flat volcano.