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 of volcano

• 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

The 103-room property began in 1991 with the vision of architect Jaime Mikowski who wanted to harness a portion of the Tabacón River for the purpose of wellness, and the result is Costa Rica’s finest thermal spa, ideally situated at the base of the Arenal volcano. —Condé Nast, Condé Nast Traveler, 24 Feb. 2026

Haleakala is famous for its sunrise as seen from the peak of the 10,000-foot tall volcano (plan six months in advance for reservations, or settle for an incredible sunset without reservations) but that’s not the only reason to visit this park. —Graham Averill, Outside, 23 Feb. 2026

Another brilliant show of Earth's power was caught on camera over the weekend when a geyser of molten rock burst from the Kilauea volcano in Hawaii. —Mary Walrath-Holdridge, USA Today, 16 Feb. 2026

The breathtaking beauty of the glen, created by the eruption of a super volcano some 420 million years ago, is overshadowed by an event that lives on in Scottish history. —Patti Nickell, Boston Herald, 15 Feb. 2026

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.