volcano
Americannoun
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volcanoes,
plural
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volcanos
plural
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a vent in the earth's crust through which lava, steam, ashes, etc., are expelled, either continuously or at irregular intervals.
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a mountain or hill, usually having a cuplike crater at the summit, formed around such a vent from the ash and lava expelled through it.
noun
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an opening in the earth's crust from which molten lava, rock fragments, ashes, dust, and gases are ejected from below the earth's surface
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a mountain formed from volcanic material ejected from a vent in a central crater
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An opening in the Earth's crust from which lava, ash, and hot gases flow or are ejected during an eruption.
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A usually cone-shaped mountain formed by the materials issuing from such an opening. Volcanoes are usually associated with plate boundaries but can also occur within the interior areas of a tectonic plate. Their shape is directly related to the type of magma that flows from them—the more viscous the magma, the steeper the sides of the volcano.
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◆ A volcano composed of gently sloping sheets of basaltic lava from successive volcanic eruptions is called a shield volcano. The lava flows associated with shield volcanos, such as Mauna Loa, on Hawaii, are very fluid.
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◆ A volcano composed of steep, alternating layers of lava and pyroclastic materials, including ash, is called a stratovolcano. Stratovolcanos are associated with relatively viscous lava and with explosive eruptions. They are the most common form of large continental volcanos. Mount Vesuvius, Mount Fuji, and Mount St. Helens are stratovolcanos.
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Also called composite volcano
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See more at hot spot island arc tectonic boundary volcanic arc
Discover More
Volcanoes tend to occur along the edges of tectonic plates.
Eruptions and lava flows associated with them can be very destructive. (See Mount Saint Helens and Mount Vesuvius.)
Other Word Forms
Noun Inflected Forms
Etymology
Origin of volcano
1605–15; < Italian < Latin Volcānus, variant of Vulcānus Vulcan
Explanation
When the earth's crust cracks open and spews hot lava and gases, you've got a volcano on your hands. You better run. The noun volcano comes from the name of the Roman god of fire, Vulcan. The Romans believed Vulcan had a forge in Mt. Etna, a volcano in Italy. The term can be applied to a vent in a planet's surface or crust. Lava, ash, and gas escape through the vent. The term volcano can also apply to a mountain created by such a vent.
Vocabulary lists containing volcano
Physical Geography - Introductory
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Physical Geography - Middle School
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The United States
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
Lava flowing from a volcano eventually cools and hardens into rock, while water in a lake can freeze into ice during a cold winter.
From Science Daily ● Aug. 22, 2026
The Fuego volcano, located between the Escuintla, Chimaltenango, and Sacatepéquez regions, registered an increase in its activity on Monday, prompting Guatemalan authorities to declare an "orange alert" - the second highest emergency.
From BBC ● Aug. 4, 2026
Guatemalan authorities issued the country's second-highest emergency alert level on Monday after a major eruption of Central America's most active volcano, prompting the evacuation of nearby villages.
From Barron's ● Aug. 4, 2026
Dramatizations of the several lives studied put figurative flesh on the petrified bodies of the volcano victims, and those who escaped such a fate.
From The Wall Street Journal ● Jul. 21, 2026
If the volcano had erupted even an hour later, many more scientists would’ve been within the devastated area.
From "Mountain of Fire" by Rebecca E. F. Barone
Turtle said Dragonfly will be looking for signs of earthquakes or volcanoes that might allow hydrocarbons like methane to move between the surface and the ice-covered ocean.
From Los Angeles Times ● Aug. 22, 2026
Fuego, one of the most active volcanoes in the Western Hemisphere, started spewing lava and ash on Monday.
From BBC ● Aug. 4, 2026
Scientists have identified a heat-driven process inside magma that could help explain why volcanoes with similar characteristics sometimes erupt in very different ways.
From Science Daily ● Aug. 1, 2026
A vast reservoir of magma beneath Japan's Kikai caldera appears to be filling again, offering scientists a rare glimpse into how some of Earth's largest volcanoes recover after catastrophic eruptions.
From Science Daily ● Jul. 29, 2026
Most of us, when we think of volcanoes, think of the classic cone shapes of a Fuji or Kilimanjaro, which are created when erupting magma accumulates in a symmetrical mound.
From "A Short History of Nearly Everything" by Bill Bryson
One of the most active volcanos on Earth, Kilauea erupts every 2 to 3 years on average.
From Science Magazine ● May 27, 2024
In addition to lava, volcanos eject large amounts of pumice, ashes and gases as a fast-moving flow, known as "pyroclastic flow," and its sediments are a valuable data source on past eruptions.
From Science Daily ● Feb. 22, 2024
It seemed like an eruption might be imminent … but volcanos are fickle.
From Slate ● Dec. 20, 2023
For the past few days, we'd been walking on black beaches formed by lava, driving past enormous craters left by dormant volcanos.
From Salon ● Nov. 17, 2023
The hot cakes rose like little hassocks, and small volcanos formed and erupted on them until they were ready to be turned.
From "East of Eden" by John Steinbeck
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
