lava

American  

[lah-vuh, lav-uh] / ˈlɑ və, ˈlæv ə /

noun

1. the molten, fluid rock that issues from a volcano or volcanic vent.

2. the rock formed when this solidifies, occurring in many varieties differing greatly in structure and constitution.

---

lava British  

/ ˈlɑːvə /

noun

1. magma emanating from volcanoes and other vents

2. any extrusive igneous rock formed by the cooling and solidification of molten lava

---

lava Scientific  

/ lä′və /

1. 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).

2. Compare magma

3. 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.

4. See also aa pahoehoe pillow lava

---

lava Cultural  

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

---

Usage

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.

Etymology

Origin of lava

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

Explanation

Is lava flowing through your street? Then you'd better run! Lava is the hot liquid rock that pours from an erupting volcano. Under the earth's crust is molten rock called magma, along with explosive gases. Under the right conditions, the gases send the magma up through volcanoes, which act as vents in the surface of the earth. When magma reaches the surface, it becomes lava. Over time, the hot molten lava cools and becomes very hard; layers of lava eventually form mountains.

Example Sentences

That was a wonderfully eccentric romance forged in molten lava.

From Los Angeles Times • Jun. 5, 2026

Among them is his Oscar-shortlisted “The Deep,” the tale of an Icelandic fisherman who survived a 1984 shipwreck for six hours in 41-degrees-Fahrenheit ocean water, swam to shore and then walked barefoot over lava fields.

From The Wall Street Journal • Apr. 23, 2026

The confession results in confusion and anger erupting like molten lava from all sides, instantly corroding Emma’s bond with Charlie and her relationships with their friends.

From Salon • Apr. 9, 2026

That temperature exceeds molten lava and goes far beyond anything previously achieved for this class of technology.

From Science Daily • Apr. 7, 2026

But the paths are made of a smooth surface with little holes in it, like lava rock, so it’s no big deal if you’re barefoot the entire time.

From "Everything Sad Is Untrue" by Daniel Nayeri

Related Words

• basalt
• magma
• slag