WordNet
volcano
名詞
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火口 噴火口
a fissure in the earth's crust (or in the surface of some other planet) through which molten lava and gases erupt.
溶岩とガスが噴出する地殻(あるいは他の惑星の表面)の裂け目。
言い換え - 
										
火山
a mountain formed by volcanic material.
火山性の物質でできた山。