volcano

noun

vol·​ca·​no väl-ˈkā-(ˌ)nō 

vȯl-

plural volcanoes or volcanos

1

: a vent in the crust of the earth or another planet or a moon from which usually molten or hot rock and steam issue

also : a hill or mountain composed wholly or in part of the ejected material

2

: something of explosively violent potential

Illustration of volcano

• 1 cinder cone
• 2 shield volcano
• 3 stratovolcano

Synonyms

• time bomb
• powder keg
• flash point

Examples of volcano in a Sentence

The volcano last erupted 25 years ago.

after months of tension the roommates' living situation was a volcano

Recent Examples on the Web

Under the water lies an ancient volcano with an enormous amount of sediment deposited behind it — 35 km long, 7 km wide, and 163 meters thick. —Elizabeth Fernandez, Big Think, 4 Sep. 2025

Seek Adventure Challenge yourselves by hiking Mount Kilimanjaro, a dormant volcano in Tanzania; trekking mountain gorillas in Rwanda or Uganda; flying in a hot air balloon over the Masai Mara; or zip-lining over Zimbabwe’s Victoria Falls. —Karin Jones, Travel + Leisure, 4 Sep. 2025

Just after midnight, lava began to emerge from the volcano's north vent in Halemaumau Crater, the USGS said. —Daniel Orton, MSNBC Newsweek, 3 Sep. 2025

Wetlands need restoration to impound phosphorus that pours from extinct volcanoes and prevent the growth of deadly algae. —Debra Utacia Krol, USA Today, 2 Sep. 2025

Word History

Etymology

Italian or Spanish; Italian vulcano, from Spanish volcán, ultimately from Latin Volcanus Vulcan

First Known Use

1665, in the meaning defined at sense 1

Phrases Containing volcano

• shield volcano

Kids Definition

volcano

noun

vol·​ca·​no väl-ˈkā-nō 

vȯl-

plural volcanoes or volcanos

: a vent in the earth's crust from which melted or hot rock and steam come out

also : a hill or mountain composed entirely or in part of the material thrown out

Etymology

from Italian or Spanish; Italian vulcano "volcano," from Spanish vulcán, from Latin Volcanus, Vulcanus "Vulcan (Roman god of fire)"

Word Origin

The ancient Greeks and Romans had many gods and goddesses. Each of these deities was in charge of a special kind of work or an aspect of nature. Many of the happenings in nature were explained in myth as the actions of one or more of these gods or goddesses. The Roman god of fire was known as Vulcanus in Latin (Vulcan in English). He was thought to live inside Mount Etna, a volcano on the island of Sicily. Vulcan was a giant who worked as a blacksmith, forging the thunderbolts for Jupiter, king of the gods. The smoke and occasional fiery rocks and lava that came from Mount Etna were thought to be from Vulcan's forge. That is how his name came to be applied to a mountain that sometimes spews forth fire and smoke.