A volcano is a hill or mountain that has a crater through which lava, gas and rock fragments erupt or have previously erupted from the crust of the Earth. Lava is molten rock that is called magma when it is still beneath the Earth's surface.
Inactive volcanoes are expected to erupt again at some point, despite being dormant for thousands of years. Examples of inactive volcanoes are Mount Fuji and Mount Rainier.
Extinct volcanoes are ones that have not erupted for more than 10,000 years, but scientists believe will never erupt again.Learn more about Volcanoes