cavern
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source: By P199 - Own work, CC BY-SA 3.0
noun
a cave, or a chamber in a cave, typically a large one.
大きな洞窟［ほら穴］.
used in similes and comparisons to refer to a vast, dark space:
広く暗い場所［部屋］
e.g. the dark cavern of the main performance hall
e.g. rouses me from the cavern of sleep.
ORIGIN
late Middle English: from Old French caverne or from Latin caverna, from cavus ‘hollow’. Compare with cave1.