caldera
kal-DEHR-ah
A large, roughly circular depression formed by the collapse of a volcano's summit after an eruption empties or partially empties the magma chamber beneath it. The mountain falls into the void it created. Calderas can be miles across and thousands of feet deep. Crater Lake in Oregon fills a caldera. Yellowstone sits inside one. The word names the absence — not the mountain but the hole where the mountain was.
Etymology
Spanish caldera, a cauldron or large pot, from Latin caldaria, a cooking pot. The shape is the pot — a vast bowl in the earth.
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