Word of the Day


Liz Potter
Written by Liz Potter


a large volcano

View the full definition in the Macmillan Dictionary.

Origin and usage

The noun supervolcano was formed in the 1920s from the prefix ‘super-‘ meaning ‘more, better or bigger than usual’ and the noun ‘volcano’ which comes from the Italian ‘vulcano’.


A supervolcano is a very large volcano that is capable of producing a massive eruption. The term has a technical definition: a supervolcano is one that has had an eruption of magnitude 8, the highest possible magnitude on the scale used to measure eruptions. A magnitude 8 eruption produces a volume of material greater than 1,000 cubic kilometres or 240 cubic miles. While there have been no magnitude 8 eruptions in historical times, level 7 eruptions have occurred within the past 2000 years, most recently in Indonesia in 1815. Another was the eruption over 3500 years ago that resulted in the present form of the Greek island of Santorini. Supervolcano is an entry in Macmillan Dictionary’s Open Dictionary, one of many contributed by a user in Iran. One of the delights of the OD is the contributions made by experts in one field or another; other recent entries contributed by this user include fossil record, geological footprint, and the geological ages the Cambrian and the Holocene. We are grateful for all your contributions, so do keep them coming.


“The effects [of an eruption] could be sufficiently severe to threaten the fabric of civilisation.”
(Greg Breining, Super Volcano: The Ticking Time Bomb Beneath Yellowstone National Park)

New research about the Yellowstone supervolcano shows it could erupt sooner than expected.”

Related words

active, dormant, erupt, lava

Browse related words in the Macmillan Thesaurus.

About the author

Liz Potter

Liz Potter

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