lava Meaning, Definition & Usage

noun rock that in its molten form (as magma) issues from volcanos; lava is what magma is called when it reaches the surface

It. lava lava, orig. in Naples, a torrent of rain overflowing the streets, fr. It. & L. lavare to wash. See Lave.

The melted rock ejected by a volcano from its top or fissured sides. It flows out in streams sometimes miles in length. It also issues from fissures in the earth's surface, and forms beds covering many square miles, as in the Northwestern United States. ✍ Lavas are classed, according to their structure, as scoriaceous or cellular, glassy, stony, etc., and according to the material of which they consist, as doleritic, trachytic, etc.