Longman Dictionary of Contemporary English - volcano

~ n plural volcanoes or volcanos a mountain with a large hole at the top, through which hot rocks, lava, and ash sometimes rise into the air from inside the earth  (Pompeii was destroyed when the volcano erupted in 79AD. | active volcano (=a volcano that may explode at any time) | dormant volcano (=a volcano that is not active at present) | extinct volcano (=a volcano that is no longer active))