a mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust.

fumarole
trench
funnel
volcano

A volcano is a mountain or hill, typically conical, that has a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the Earth's crust.