a cave, esp. one that is large and mostly underground.

Pathology . a cavity that is produced by disease, esp. one produced in the lungs by tuberculosis.

to enclose in or as if in a cavern.

to hollow out to form a cavern.

noun

cave , grotto , hole , pothole , subterrane , subterranean areanotes:cavern is more vague and rhetorical than cave ; a cavern is a large cave , cavity , croft , den , hollow