[ lah-vuh, lav-uh ]
/ ˈlɑ və, ˈlæv ə /
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the molten, fluid rock that issues from a volcano or volcanic vent.
the rock formed when this solidifies, occurring in many varieties differing greatly in structure and constitution.
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Origin of lava

1740–50; <Italian, originally Neapolitan dialect: avalanche <Latin lābēs a sliding down, falling, akin to lābī to slide


1. larva, lava 2. lava , magma
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023


What’s the difference between lava and magma?

Lava is what molten (melted) rock is called when it flows out of a volcano or volcanic vent. Magma is what molten rock is called when it’s under the earth’s surface.

To be clear, in popular use, lava and magma are essentially different names for the same liquid-hot, charred orange ooze—which name is used depends on whether it is above or below the surface.

However, geologists and volcanologists have their reasons for using the two different terms to distinguish between forms of what is the same substance.

Magma doesn’t always become lava—sometimes it cools and solidifies beneath the earth’s surface. Sometimes, it collects in what’s known as a magma chamber. When it does reach the surface, it flows out as lava. The rock that’s formed when it hardens and cools can also be called lava, though this use of the term is uncommon outside of technical, scientific contexts.

The word lava is perhaps the more well-known of the two because that’s the one we see when volcanoes erupt (or when the floor turns into it).

Here is an example of lava and magma used correctly in the same sentence.

Example: Lava began flowing from the volcano three days after scientists detected movement of magma underground.

Want to learn more? Read the full breakdown of the difference between lava and magma.

Quiz yourself on lava vs. magma!

Should lava or magma be used in the following sentence?

The eruption resulted in a steady flow of _____ from the volcano.

How to use lava in a sentence

British Dictionary definitions for lava

/ (ˈlɑːvə) /

magma emanating from volcanoes and other vents
any extrusive igneous rock formed by the cooling and solidification of molten lava

Word Origin for lava

C18: from Italian (Neapolitan dialect), from Latin lavāre to wash
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for lava

[ lävə ]

Molten rock that flows from a volcano or from a crack in the Earth. Most lava flows at a rate of a few kilometers per hour, but rates as high as 60 km (37 mi) per hour have been observed. Lava that contains abundant iron- and magnesium-rich components usually erupts with temperatures between 1,000°C and 1,200°C (1,832deg;F and 2,192°F). Lava that contains abundant silica- and feldspar-rich components usually erupts with temperatures between 800°C and 1,000°C (1,472deg;F and 1,832°F). Compare magma.
The igneous rock formed when this substance cools and hardens. Depending on its composition and the rate at which it cools, lava can be glassy, very finely grained, ropelike, or coarsely grained. When it cools underwater, it cools in pillow-shaped masses. See also aa pahoehoe pillow lava.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for lava


A type of igneous rock that is formed when molten magma from a volcano hardens.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.