The present participle of 'cavern,' meaning to form or enlarge caverns, or to hollow out like a cavern.
From 'cavern' (Latin 'caverna') plus the present participle '-ing'; describes the action of cavern formation or hollowing out.
Water is constantly 'caverning' limestone bedrock—dissolving it grain by grain over centuries—which is why some of the world's largest cave systems are found in karst terrain.
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